an amateur satellite primer

Space Communications 231

SpaceCommunications

Chapter 23

An Amateur Satellite PrimerMost amateurs are familiar with repeater

stations that retransmit signals to providewider coverage Repeaters achieve this bylistening for signals on one frequency andimmediately retransmitting whatever theyhear on another frequency Thanks to re-peaters small low-power radios can com-municate over thousands of squarekilometers Unfortunately many ama-teurs are not familiar with the best repeat-ers that have ever existed These are theamateur satellites that hams have beenusing for 40 years (See the sidebar ldquoTiredof the Same Old QSOsrdquo)

This is essentially the function of anamateur satellite as well Of course whilea repeater antenna may be up to a few hun-dred meters above the surrounding terrainthe satellite is hundreds or thousands ofkilometers above the surface of the EarthThe area of the Earth that the satellitersquossignals can reach is therefore much largerthan the coverage area of even the bestEarth-bound repeaters It is this character-istic of satellites that makes them attrac-tive for communication Most amateursatellites act as analog repeaters retrans-mitting CW and voice signals exactly asthey are received as packet store-and-for-ward systems that receive whole messagesfrom ground stations for later relay or asspecialized Earth-looking camera systemsthat can provide some spectacular viewsSee Fig 232 an image of a town in thewestern US

Amateur satellites have a long historyof performing worldwide communications

Fig 231mdashN1JEZs portable microwave satellite station

services for amateurs See the sidebarldquoAmateur Satellite Historyrdquo

LINEAR TRANSPONDERS ANDTHE PROBLEM OF POWER

Most analog satellites are equipped withlinear transponders These are devices

that retransmit signals within a band offrequencies usually 50 to 250 kHz wideknown as the passband Since the lineartransponder retransmits the entire band anumber of signals may be retransmittedsimultaneously For example if threeSSB signals (each separated by as little

N1JEZ

From The N3UJJCOM Document LibraryFrom The N3UJJCOM Document Library

232 Chapter 23

Fig 233mdashA linear transponder acts much like a repeater except that it relays anentire group of signals not just one signal at a time In this example the satelliteis receiving three signals on its 23-cm uplink passband and retransmitting themon its 13-cm downlink passband

as 5 kHz) were transmitted to the satellitethe satellite would retransmit all three sig-nalsmdashstill separated by 5 kHz each (seeFig 233) Just like a terrestrial repeaterthe retransmissions take place on frequen-cies that are different from the oneson which the signals were originallyreceived

Some linear transponders invert theuplink signals In other words if you trans-

Fig 232mdashUO-36 captured this image ofa well-known city in the western USNeed a hint Think ldquoCaesarrsquos Palacerdquo

Tired of the Same Old QSOs Break out of Orbit and Set your Course for theldquoFinal Frontierrdquo

Satellite-active hams comprise a relatively smallsegment of our hobby primarily because of an unfortu-nate fiction that has been circulating for many yearsmdashthemyth that operating through amateur satellites is overlydifficult and expensive

Like any other facet of Amateur Radio satellite hamming isas expensive as you allow it to become If you want to equipyour home with a satellite communication station that wouldmake a NASA engineer blush it will be expensive If you wantto simply communicate with a few low-Earth-orbiting birdsusing less-than-state-of-the-art gear a satellite station is nomore expensive than a typical HF or VHF setup In manycases you can communicate with satellites using your presentstation equipmentmdashno additional purchases are necessary

Does satellite hamming impose a steep learning curve Not

really You have to do a bit of work and invest some brainpower to be successful but the same can be said ofDXing contesting traffic handling digital operating or anyother specialized endeavor You are after all communi-cating with a spacecraft

The rewards for your efforts are substantial makingsatellite operating one of the most exciting pursuits inAmateur Radio There is nothing like the thrill of hearingsomeone responding to your call from a thousand milesaway and knowing that he heard you through a satellite(The same goes for the spooky spellbinding effect ofhearing your own voice echoing through a spacecraft asit streaks through the blackness of space) Satellitehamming will pump the life back into your radioexperience and give you new goals to conquer

mit to the satellite at the bottom of theuplink passband your signal will appearat the top of the downlink passband Inaddition if you transmit in lower sideband(LSB) your downlink signal will be inupper sideband (USB) See Fig 234 Sat-ellite passbands are usually operated ac-cording to the courtesy band plan asshown Transceivers designed for satelliteuse usually include features that cope withthis confusing flip-flop

Over the years the number of amateurbands available on satellites has in-creased To help in easily identifyingthese bands a system of ldquoModesrdquo hasbeen created In the early years referenceto these Modes was by a single letter(Mode A Mode B etc) but with thelaunch of more satellites the opportuni-

ties greatly increased and it was neces-sary to show both the uplink and down-link bands See Table 231 SatelliteOperating Modes

Linear transponders can repeat any typeof signal but those used by amateur satel-lites are primarily designed for SSB andCW The reason for the SSB and CW pref-erence has a lot to do with the hassle ofgenerating power in space Amateur sat-ellites are powered by batteries which arerecharged by solar cells ldquoSpace ratedrdquosolar arrays and batteries are very expen-sive They are also heavy and tend to takeup a substantial amount of space Thanksto meager funding hams donrsquot have theluxury of launching satellites with largepower systems such as those used by com-mercial birds We have to do the best we



Table 231Satellite Operating ModesFrequency Band Letter Designation

HF 21-30 MHz HVHF 144-148 MHz VUHF 435-438 MHz U126-127 GHz L240-245 GHz S56 GHz C104 GHz X24 GHz K

New Designation Old Designation

(Transmit First Letter Receive Second Letter)Mode UV Mode BMode VU Mode JMode US Mode SMode LU Mode LMode VH Mode AMode HSMode LSMode LXMode CX

can within a much more limited ldquopowerbudgetrdquo

So what does this have to do with SSBor any other mode Think duty cyclemdashtheamount of time a transmitter operates atfull output With SSB and CW the dutycycle is quite low A linear satellite tran-sponder can retransmit many SSB and CWsignals while still operating within thepower generating limitations of an ama-teur satellite It hardly breaks a sweat

Now consider FM An FM transmitteroperates at a 100 duty cycle whichmeans it is generating its full output withevery transmission Imagine how muchpower a linear transponder would need toretransmit say a dozen FM signalsmdashalldemanding 100 output

Having said all that there are a fewvery popular FM repeater satellites How-ever they do not use linear transpondersThey retransmit only one signal at a time

FINDING A SATELLITEBefore you can communicate through

a satellite you have to know what satel-lites are available and when they areavailable (See sidebar ldquoCurrent AmateurSatellitesrdquo) This isnrsquot quite as straight-

Fig 234mdashThe OSCAR satellite bandplan allows for CW-only mixed CWSSB and SSB-only operationCourteous operators observe thisvoluntary band plan at all times

Fig 235mdashAn example of a satellite in ahigh elliptical orbit

forward as it seemsAmateur satellites do not travel in geo-

stationary orbits like many commercialand military spacecraft Satellites in geo-stationary orbits cruise above the Earthrsquosequator at an altitude of about 35000kilometers From this vantage point thesatellites can ldquoseerdquo almost half of ourplanet Their speed in orbit matches therotational speed of the Earth itself so thesatellites appear to be ldquoparkedrdquo at fixedpositions in the sky They are available tosend and receive signals 24 hours a dayover an enormous area

Of course amateur satellites could beplaced in geostationary orbits The prob-lem isnrsquot one of physics itrsquos money andpolitics Placing a satellite in geostation-ary orbit and keeping it on station costs agreat deal of moneymdashmore than any oneamateur satellite organization can affordAn amateur satellite group could ask simi-lar groups in other areas of the world tocontribute money to a geostationary satel-lite project but why should they Wouldyou contribute large sums of money to asatellite that may never ldquoseerdquo your part ofthe world Unless you are blessed withphenomenal generosity it would seemunlikely

Fig 236mdashTabular output from an orbit prediction program showing time andposition information for AO-16

Instead all amateur satellites are eitherlow-Earth orbiters (LEO) or they travel invery high elongated orbits See Fig 235Either way they are not in fixed positionsin the sky Their positions relative to yourstation change constantly as the satelliteszip around the Earth This means that youneed to predict when satellites will appearin your area and what paths theyrsquoll take asthey move across your local sky

Yoursquoll be pleased to know that there issoftware available that handles this pre-diction task very nicely A bare-bones pro-gram will provide a schedule for thesatellite you choose A very simple sched-ule might look something like Fig 236showing the antenna pointing angles foreach minute of a pass for AO-16

The time is usually expressed in UTC


234 Chapter 23

The Amateur Radio satelliteprogram began with the designconstruction and launch ofOSCAR I in 1961 under theauspices of the Project OSCARAssociation in California Theacronym ldquoOSCARrdquo which hasbeen attached to almost allAmateur Radio satellite designa-tions on a worldwide basisstands for Orbiting SatelliteCarrying Amateur Radio ProjectOSCAR was instrumental inorganizing the construction ofthe next three Amateur RadiosatellitesmdashOSCARs II III and IVThe Radio Amateurrsquos SatelliteHandbook published by ARRLhas details of the early days ofthe amateur space program

In 1969 the Radio AmateurSatellite Corporation (AMSAT)was formed in Washington DCAMSAT has participated in thevast majority of amateur satelliteprojects both in the UnitedStates and internationallybeginning with the launch ofOSCAR 5 Now many countrieshave their own AMSAT organiza-tions such as AMSAT-UK inEngland AMSAT-DL in Ger-many BRAMSAT in Brazil andAMSAT-LU in Argentina All ofthese organizations operateindependently but may cooper-ate on large satellite projectsand other items of interest to theworldwide Amateur Radiosatellite community Because ofthe many AMSAT organizationsnow in existence the US AMSATorganization is frequentlydesignated AMSAT-NA

Beginning with OSCAR 6amateurs started to enjoy theuse of satellites with lifetimesmeasured in years as opposedto weeks or months The opera-tional lives of OSCARs 6 7 8and 9 for example rangedbetween four and eight years Allof these satellites were lowEarth orbiting (LEO) with alti-tudes approximately 800-1200km LEO Amateur Radio satel-lites have also been launched byother groups not associated withany AMSAT organization such

Digital CommunicationsExperiment (DCE) was notopen to the general AmateurRadio community although itwas utilized by designatedldquogatewayrdquo stations The firstsatellite with store-and-forwardcapability open to all amateurswas the Japanese Fuji-OSCAR12 satellite launched in 1986FO-12 was succeeded byFO-20 launched in 1990 andFO-29 launched in 1996

By far the most popularstore-and-forward satellites arethe PACSATs utilizing thePACSAT Broadcast ProtocolThese PACSATs fall into twogeneral categories mdash theMicrosats based on technol-ogy developed by AMSAT-NAand the UOSATs based ontechnology developed by theUniversity of Surrey in the UKWhile both types are physicallysmall spacecraft the Microsatsrepresent a truly innovativedesign in terms of size andcapability A typical Microsat isa cube measuring 23 cm (9 in)on a side and weighing about10 kg (22 lb) The satellite willcontain an onboard computerenough RAM for the messagestorage two to three transmit-ters a multichannel receivertelemetry system batteries andthe battery chargingpowerconditioning system

Amateur Radio satelliteshave evolved to provide threeprimary types of communica-tion services mdash analog tran-sponders for real-time CW andSSB communication digitalstore-and-forward for non real-time communication and directldquobent-piperdquo single-channel FMrepeaters Which of thesetypes interest you the most willprobably depend on yourcurrent Amateur Radio operat-ing habits Whatever yourpreference this section shouldprovide the information to helpyou make a successful entryinto the specialty of amateursatellite communications

as the Radio Sputniks 1-8 andthe ISKRA 2 and 3 satelliteslaunched by the former SovietUnion

The short-lifetime LEO satel-lites (OSCARs I through IV and5) are sometimes designated thePhase I satellites while the long-lifetime LEO satellites aresometimes called the Phase IIsatellites There are otherconventions in satellite namingthat are useful to know First itis common practice to have onedesignation for a satellite beforelaunch and another after it issuccessfully launched ThusOSCAR 40 (discussed later) wasknown as Phase 3D beforelaunch Next the AMSATdesignator may be added to thename for example AMSAT-OSCAR 40 or just AO-40 forshort Finally some otherdesignator may replace theAMSAT designator such as thecase with Japanese-built Fuji-OSCAR 29 (FO-29)

In order to provide widercoverage areas for longer timeperiods the high-altitude Phase3 series was initiated Phase 3satellites often provide 8-12hours of communications for alarge part of the NorthernHemisphere After losing the firstsatellite of the Phase 3 series toa launch vehicle failure in 1980AO-10 was successfullylaunched and became opera-tional in 1983 AO-13 the follow-up to the AO-10 mission waslaunched in 1988 and re-enteredthe atmosphere in 1996 Thesuccessor to AO-13 AO-40 waslaunched on November 16 2000from Kourou French Guiana

Satellites providing store-and-forward communication servicesusing packet radio techniquesare generically called PACSATsFiles stored in a PACSATmessage system can be any-thing from plain ASCII text todigitized pictures and voice

The first satellite with a digitalstore-and-forward feature wasUoSAT-OSCAR 11 UO-11rsquos

Amateur Satellite History



Fig 237mdashThecommunicationsrange circles orldquofootprintsrdquo overNorth America

Current Operational Amateur SatellitesOSCAR 7 AO-7 was launched

November 15 1974 by a Delta 2310from Vandenberg CA AO-7rsquosoperating status is semi-operationalin sunlight only After being declareddead in mid 1981 due to batteryfailure AO-7 has miraculouslysprung back to life It will only be onwhen in sunlight and off in eclipseAO-7 will reset each orbit and maynot turn on each time

OSCAR 11 UO-11 a scientificeducational low-orbit satellite wasbuilt at the University of Surrey inEngland and launched on March 11984 This UoSat spacecraft hasalso demonstrated the feasibility ofstore-and-forward packet digitalcommunications and is operationalwith telemetry downlinks only

OSCAR 16 AO-16 also knownas PACSAT was launched inJanuary 1990 A digital store-and-forward packet radio file server ithas an experimental S-band beaconat 2401143 MHz AO-16 is onlysemi-operational with the 1200-bauddigipeater for APRS service

OSCAR 26 IO-26 was launchedon September 26 1993 is semi-operational and now serves as a

1200-baud digipeater for APRSservice

RS 15 launched in December1994 is a Mode VH spacecraft itsuplink is on the 2m band and itsdownlink is on 10m

OSCAR 27 AO-27 was launchedin September 1993 along withOSCAR 26 It features a mode VUanalog FM repeater Because of theneed to conserve power OSCAR 27is usually only available duringdaylight passes

OSCAR 29 FO-29 launched fromJapan in 1996 in a low earth orbit Itoperates with a mode VU analogtransponder

OSCAR 44 NO-44 also known asPCSAT was launched on September30 2001 from Kodiak AlaskaPCSAT is a 1200-baud APRSdigipeater designed for use bystations using hand-held or mobiletransceivers The operational statusof PCSAT is uncertain and subject tochange due to power availability

OSCAR 50 SO-50 also known asSAUDISAT-1C was launchedDecember 20 2002 aboard aconverted Soviet ballistic missile

from Baikonur Cosmodrome SO-50carries several experiments includ-ing a mode UV FM amateur re-peater The repeater is available toamateurs as power permits using a670 Hz uplink tone for on-demandactivation

OSCAR 51 also known as Echowas launched on June 29 2004 fromthe Baikonur Cosmodrome Echocarries a FM repeater capable of 144MHz andor 12 GHz uplink with a435 MHz andor 24GHz downlinkThe satellite also includes an AX25digital PACSAT BBS and a PSK31uplink on 28 MHz

VUSat-OSCAR 52 was launchedon May 5 2005 Within 24 hours itsMode UV transponder was open forbusiness and hams were reportingexcellent signals The first IndianAmateur Radio satellite carries two1-W linear transponders for SSBand CW communication althoughonly one transponder is operationalat a time OSCAR 52 travels in apolar sun-synchronous orbit at analtitude of 632 times 621 km with aninclination of 978 deg with respectto the equator

AO-16 will appear above your horizonbeginning at 0516 UTC on January 30 Thebird will ldquoriserdquo at an azimuth of 164deg orapproximately south-southeast of yourstation The elevation refers to thesatellitersquos position above your horizon in

degreesmdashthe higher the better A zero-degree elevation is right on the horizon90deg is directly overhead

By looking at this schedule you can seethat the satellite will appear in your south-southeastern sky at 0516 UTC and will rise

quickly to an elevation of 70deg by 0524The satellitersquos path will curve further tothe east and then directly to the north as itrises Notice how the azimuth shifts from164deg at 0516 UTC to 0deg at 0524 This isnearly a direct overhead pass of AO-16and it sets in the north-northwest at 348deg

The more sophisticated the software themore information it usually provides in theschedule table The software may also dis-play the satellitersquos position graphically asa moving object superimposed on a map ofthe world Some of the displays used bysatellite prediction software are visuallystunning This view Fig 237 is providedby Nova for Windows from NorthernLights Software Associates

Satellite prediction software is widelyavailable on the Web Some of the simplerprograms are freeware The AMSAT-NAWeb site has the largest collection of satel-lite software for just about any computeryou can imagine Most AMSAT softwareisnrsquot free but the cost is reasonable and thefunds support amateur satellite programs

Whichever software you choose thereare two key pieces of information you mustprovide before you can use the programs

(1) Your position The software musthave your latitude and longitude before itcan crank out predictions for your sta-


236 Chapter 23

Fig 238mdashW2RS shows another popularLEO FM antenna for hand-heldoperations

Fig 239mdashThe hand-held ldquoArrowrdquo gainantenna is popular for LEO FMoperations (Photo courtesy TheAMSAT Journal SepOct 1998)

Fig 2310mdashEggbeater antennas are popu-lar for base station LEO satellite opera-tion This EB144 eggbeater is for 2 m

Fig 2311mdashThis EB-432 eggbeaterantenna for 70-cm operation is smallenough to put in an attic Antenna gainpattern is helped with the radialsplaced below the antenna

tion The good news is that your positioninformation doesnrsquot need to be extremelyaccurate Just find out the latitude andlongitude of your city or town (the publiclibrary would have this data as wouldany nearby airport) and plug it into theprogram

(2) Orbital elements This is the infor-mation that describes the orbits of the sat-ellites You can find orbital elements (oftenreferred to as Keplerian elements) at theAMSAT Web site and through many othersources on the Internet You need to updatethe elements every few months Many sat-ellite programs will automatically read inthe elements if they are provided as ASCIItext files The less sophisticated programswill require you to enter them by handAutomatically updated software is highlyrecommended itrsquos too easy to make a mis-take with manual entries

GETTING STARTED WITHTHE FM BIRDS

Do you like elevated FM repeaters withwide coverage areas Then check out theAO-27 and AO-51 FM repeater satellitesFrom their low-Earth orbits these satellitescan hear stations within a radius of 2000miles in all directions

You can operate the FM satellites witha basic dual band VHFUHF FM trans-ceiver and even a good FM HT as someamateurs have managed Assuming thatthe transceiver is reasonably sensitive youcan use a good ldquorubber duckrdquo antenna as inFig 238 Some amateurs have even man-aged to work the FM birds with HTs

coupled to multi-element directionalantennas such as the popular ArrowAntenna Fig 239 Of course this meansthey must aim their antennas at the satel-lites as they cross overhead

High quality omnidirectional antennasfor LEO service come in quite a number offorms and shapes M2 Enterprises has theirEB-144 and EB-432 Eggbeater antennasFig 2310 and Fig 2311 which have provento be very useful and do not require anyrotators for control The Quadrifilar omni-directional antenna Fig 2312 has beenaround for a long time as has the turnstile-over-reflector antenna Fig 2313

For even better performance at themodest cost of a simple TV antenna rota-tor check out the fixed elevation TexasPotato Masher antenna by K5OE Fig2314 This antenna provides a dual bandsolution for medium gain directionalantennas for LEO satellite operations Thisis a considerable improvement over omni-directional antennas and does not requirean elevation control for good performance

Start by booting your satellite trackingsoftware Check for a pass with a peakelevation of 30deg or higher As with all sat-ellites the higher the elevation the betterIf you plan to operate outdoors or awayfrom home either print the schedule to aprinter or jot down the times on a piece ofscrap paper that you can keep with you

When the satellite comes into rangeyoursquoll be receiving its signal about 5 kHzhigher than the published downlink fre-quency (see Table 232 Active AmateurSatellites Frequencies and Modes) thanksto Doppler shifting (see the sidebarldquoDown with Dopplerrdquo) So begin listen-ing on the higher frequency If you sud-denly hear the noise level droppingchances are you are picking up thesatellitersquos signal At about the midpoint ofthe pass yoursquoll need to shift your receiverdown to the published frequency and asthe satellite is heading away you may windup stepping down another 5 kHz Someoperators program these frequency stepsinto memory channels so that they cancompensate for Doppler shift at the pushof a button

Once again these FM satellites behavejust like terrestrial FM repeaters Only oneperson at a time can talk If two or morepeople transmit simultaneously the resultis garbled audio or a squealing sound onthe output The trick is to take turns andkeep the conversations short Even the bestpasses will only give you about 15 minutesto use the satellite If you strike up a con-versation donrsquot forget that there are oth-ers waiting to use the bird

The FM repeater satellites are a goodway to get started Once you get your feet



Fig 2312mdashW3KH suggests thatquadrifilar antennas can serve wellfor omnidirectional satellite stationantenna service

Table 232 ndash Active Amateur Satellites Frequencies and Modes

Satellite (SSBCW) Uplink (MHz) Downlink (MHz)

FO-29 145900-146000 435800-435900435795 (CW beacon)

RS-15 145858-145898 29354-29394VO-52 435225-435275 145875-145925

Packetmdash1200 bits

AO-16 14590 92 94 96 437051NO-44 145827 144390


GO-32 890145850 435225

FM Voice Repeaters

AO-51 145920 435300AO-27 145850 436795(Daylight passes only)]

Fig 2313mdashThe Turnstile Over Reflectorantenna has served well for LEOsatellite service for a number of years

Fig 2314mdashJerry Brown K5OE uses hisTexas Potato Masher antennas for LEOsatellite operations

wet yoursquoll probably wish you couldaccess a satellite that wasnrsquot so crowdedwhere you could chat for as long as thebird was in range You may find that avery good assist will be given to you fromthe book Working the Easy Sats byWA4YMZ and N1JEZ This is availablefrom AMSAT headquarters3 But now it istime to move up

MOVING UP TO OSCARS 29AND 52

VUSat-OSCAR 52 carries a Mode UVtransponder which means that it receivessignals on the 70-cm band and retransmitson the 2-m band Operating this satellite isdone with the equipment and antenna setupshown in Fig 2315

Once yoursquove determined when the sat-ellite is due to rise above the horizon atyour location listen for the satellitersquos CWtelemetry beacon This signal is transmit-ted constantly by the satellite and carriesinformation about the state of thesatellitersquos systems such as its battery volt-age solar-panel currents temperaturesand so on You should hear it just as thesatellite rises above the horizon As soonas you can hear the beacon start tuningacross the downlink passband

On an active day you should pick upseveral signals They will sound like nor-mal amateur SSB and CW conversationsNothing unusual about them at allmdashex-cept that the signals will be slowly driftingdownward in frequency Thatrsquos the effectof Doppler shift

Now tune your transmitterrsquos frequencyto the satellitersquos uplink passband OSCAR52 uses inverting transponders If youtransmit at the low end of the uplink pass-

band you can expect to hear your signal atthe high end of the downlink passbandGenerally speaking CW operators occupythe lower half of the transponder passbandwhile SSB enthusiasts use the upper halfas was shown in Fig 234

Assuming that you cannot hear yourown signal from the satellite on a separatereceiver the best thing to do is make yourbest guess as to where your signal willappear on the downlink and set your re-ceive frequency accordingly Send severalbrief CQs (ldquoCQ OSCAR 52 CQ OSCAR52helliprdquo) tuning ldquogenerouslyrdquo around yourguesstimated receive frequency after each

Fig 2315mdashSimple ground plane andYagi antennas can be used for low-Earth-orbit (LEO) satellite contacts


238 Chapter 23

Fig 2317mdashThe Yaesu FT-847rsquos satellitemode provides the user with a fullfeatured satellite transceiver As abonus it also covers all the HF bands

Fig 2318mdashSeveral different Mode-UV satellite-station configurations for OSCAR 52 are shown here At A separate VHFUHFmultimode transceivers are used for transmitting and receiving The configuration shown at B uses transmitting andreceiving converters or transverters with HF equipment At C a multimode multiband transceiver can perform bothtransmitting and receiving function full duplex in one package The Ten-Tec 2510 shown at D contains a 435-MHztransmitter and a 2-m to 10-m receiving converter

Fig 2316mdashVUSat-OSCAR 52 heads fororbit

one The station that is answering your callwill also be making his or her best guessabout where you are listening

The Japanese Fuji OSCAR FO-29 isalso a linear transponder bird that func-tions much like OSCAR 52 The maindifference is that it listens on 2 m and re-transmits on 70 cm Mode VU (FO-29also uses inverting transponders) Fewamateurs own receivers that can listen for70 cm CW and SSB so this satellite is notvery active During weekend passes how-ever you should be able to hear severalconversations taking place

Station Requirements for theOSCAR 29 and 52 Satellites

To work OSCAR 52 yoursquoll need atminimum a multiband VHFUHF SSB orCW transceiver You do not need anamplifier 50 W is more than enoughpower for the uplink In fact even 50 Wmay be too much in many instances Therule of thumb is that your signal on thedownlink should never be stronger thanthe satellitersquos own telemetry beacon

The ability to hear yourself simulta-neously on the downlink is a tremendousasset for working any satellite It allowsyou to operate full duplex as you listen tothe Doppler shifting of your own signal

giving you the opportunity to immediatelytweak your transmit frequency to compen-sate (rather than fishing for contacts usingthe haphazard half-duplex procedure de-scribed earlier)

To work OSCAR 52 in Mode UV yoursquollneed a 2-m multimode transceiver that canoperate in CW or SSB Remember thatOSCAR 52 is listening for signals on 70 cmand retransmitting on 2 m This means thatalso need a 70 cm transceiver Choose yourradios carefully A number of modernHF transceivers also include 2 m and even70 cm The problem however is that some



Fig 2319mdashSeveral different Mode-VU satellite-station configurations forOSCAR 29 are shown here At A separate VHFUHF multimode transceivers areused for transmitting and receiving The configuration shown at B usestransmitting and receiving converters or transverters with HF equipment At C amultimode multiband transceiver can perform both transmitting and receivingfunctions full duplex in one package

of these radios do not allow crossband splitsbetween VHF and HF That is they wonrsquotallow you to transmit on 70 cm and receiveon 2 m At the very least they wonrsquot allowyou to do this simultaneously One solutionthat will provide full duplex service forMode UV is the Yaesu FT-847 transceiverFig 2317 all in one neat package

Omnidirectional antennas for 2 m aresufficient for listening to OSCAR 52 Abeam on 2 m would be even better butthen you incur the cost of an antenna rota-tor that can move the antenna up and downas well as side to sidemdashthe so-called azi-muthelevation rotator or Az-El rotators

For FO-29 the ability to transmit and

receive simultaneously is a must TheDoppler effect is pronounced on the 70 cmdownlink You need to listen to your ownsignal continuously making small adjust-ments to your 2-m uplink so your voice orCW note does not slide rapidly downwardin frequency To achieve this you will needseparate 2-m and 70-cm transceivers (suchas a couple of used rigs) or a dual bandtransceiver specifically designed for sat-ellite use Fig 2318 and Fig 2319 showseveral possible combinations of equip-ment for satellite operations on 2 m and70 cm Kenwood ICOM and Yaesu havesuch radios in their product lines Thesewondrous rigs make satellite operating a

breeze although their price tags may giveyou a bit of sticker shock (about $1600)They feature full crossband duplex mean-ing that you can transmit on 2 m at thesame time you are listening on 70 cm Theyeven have the ability to work with invert-ing transponders automatically That is asyou move your receive frequency downthe transmit VFO will automatically moveup (and vice versa)

Although beam antennas and azimuthelevation rotators are not strictly neces-sary to work FO-29 they vastly improvethe quality of your signal A good compro-mise medium-gain antenna for 2 m and70 cm is shown in Fig 2314 If you decide

Down with DopplerThe relative motion between you

and the satellite causes Dopplershifting of signals As the satellitemoves toward you the frequencyof the downlink signals willincrease as the velocity of thesatellite adds to the velocity of thetransmitted signal As the satellitepasses overhead and starts tomove away from you the fre-quency will drop much the sameway as the tone of a car horn or atrain whistle drops as the vehiclemoves past the observer

The Doppler effect is differentfor stations located at differentdistances from the satellitebecause the relative velocity of thesatellite with respect to theobserver is dependent on theobserverrsquos distance from thesatellite The result is that signalspassing through the satellitetransponder shift slowly aroundthe published downlink frequencyYour job is to tune your uplinktransmittermdashnot your receivermdashtocompensate for Doppler shiftingand keep your frequency relativelystable on the downlink Thatrsquos whyit is helpful to hear your own signalcoming through the satellite If youand the station yoursquore talking toboth compensate correctly yourconversation will stay at onefrequency on the downlinkthroughout the pass If you donrsquotcompensate your signals will driftthrough the downlink passband asyou attempt to ldquofollowrdquo each otherThis is highly annoying to othersusing the satellite because yourdrifting signals may drift into theirconversations


2310 Chapter 23

Fig 2320mdashWD4FABrsquos station is typical of a full-featured HF and satelliteoperation On the bottom row L-R are IC-746 HF to 2 meter transceiverIC-821H VHF-UHF multimode transceiver topped by a home-brew power meterKLM 1200GU 12-GHz transverter home-brew multi-antenna rotator controller ontop of the station accessory control box On the top row L-R are G3RUH AO-13Telemetry Demodulator PacComm SPIRIT2 high performance packet controllerTimewave DSP-599zx audio DSP unit for the VHF-microwave operations throughthe IC-821H and the TAPR EasyTrak antenna command unit for interfacing thecomputer tracking to the antenna controller

to go the omnidirectional route yoursquollneed to add a 70-cm receive preamp at theantenna to boost the downlink signal

PHASE 3EmdashTHE NEXTGENERATION

The next Phase 3-series satelliteplanned is Phase 3E or P3E It is built ona P3C (AO-13) platform As this Hand-book went to press P3E is expected tolaunch within the next two years Cur-rently the planned transmit RF operationson P3E are R Band (47 GHz) very lowpower mdash 05 W PEP K Band (24 GHz)moderate power mdash 5 W PEP X Band (105GHz) very low medium and high powermdash up to 10 W S Band (24 GHz) highpower mdash 25 W PEP and V Band (145MHz) high power Generally high powerhere means RF output from the satellite inthe 5- to 25-W PEP range using mostlylinear transmitters that incorporateHELAPS technology Very low power onX Band is to simulate the signal strengththat Earth stations will see from a P5A(Mars mission) transmitter near the redplanet There are other modules on boardmdash such as a star sensor mdash that are proto-types for the upcoming P5A mission Re-ceive frequencies on P3E will be in C Band(56 GHz) S Band (245 GHz) L Band(12 GHz) and U Band (435 MHz) Up-dates and other useful information on P3Ecan be found on the German AMSATwebsite at wwwamsat-dlorgp3e

SATELLITE GROUND STATIONSThe keys to your enjoyable satellite

communications are in the details of yourstation One such station is illustrated inFig 2320 and Fig 2321 showing onlysome of the ways that you can achieve thisenjoyable ham radio operation The follow-ing sections will describe that station andthe options that are open for you to con-struct your own satellite station includingdiscussions of equipment and techniquesfor transmitting receiving antennas andstation accessories such as audio process-ing and antenna pointing control

TransmittingThe 23-cm (L) band is the highest band

for which commercial amateur transceiv-ers are readily available Kits and convert-ers are also available Commercialequipment such as the ICOM IC-910HFig 2322 with a 23-cm module the popu-lar Yaesu FT-736R Fig 2323 with a23-cm module and the new KenwoodTS-2000 Fig 2324 with a 23-cm moduleall provide about 10 watts of RF outputpower Of course multimode transceiverssuch as the ICOM IC-821H Fig 2325with an outboard 23-cm up-converter will

also serve the satellite station very wellSee Table 233 for a listing of suppliers ofequipment of interest to satellite operators

Stations that do not have one of thenewer transceivers with their built-in12 GHz band modules can use a separatetransverter or transmitting up-converter toachieve the L-band uplink Commonlythese up-converters employ a 2-m IF fortheir drive This generally means that aseparate 2-m receiver is needed along withthe VHFUHF transceiver as often theS-band down-converter also has a 2-m IFThe station shown in Fig 2320 is of thistype using the 2-m features of the base HFtransceiver to provide the IF for the S-banddown-converter Transmitting functionsuse the VHFUHF transceiver for uplinkson U band and L band through an up-con-verter There are a few L-band-transmit-ting up-converters on the market just forsatellite service Among these are unitsfrom Down East Microwave with its1268-144TX and from SSB-USA with itsMKU130TX and from Parabolic ABWhen you assemble your station be sureto take the necessary steps to set the RFpower drive level needed for your up-con-verter This may mean the need for a powerattenuator inserted between the trans-ceiver and up-converter

Operating experience with L-band up-links has shown that the power and antennarequirements for communications at alti-tudes up to 40000 km can be satisfied with10 W of power delivered to a 12-turn helixantenna This experience has also shownthat L-band power levels of 40 W-PEP orhigher delivered to the antenna along withantenna gains of greater than 20 dBi (4000-5600 W-PEP EIRP) are very workable foroperations at the highest altitudes depend-ing upon the satellite squint angle Apretty compact L-band antenna arrange-ment with two 22-element antennas in astacked array is shown in Fig 2321 Theseantennas have a combined gain of about215 dBi Some other experiences withL-band dish antennas have shown that a12-m offset-fed dish with a helix feed and10-W of RF power can also provide a superbuplink This dish antenna will have a prac-tical gain of about 21 dBic giving an uplinkof only 1400 W-PEP EIRP but with RHCPCircular polarization for L band makes areal uplink difference These uplinks willprovide the user a downlink that is 10-15 dB above the transponder noise floor Inmore practical terms this is an S7 to S8 sig-nal over a S3 transponder noise floor in theillustrated station a very comfortable copyfor the capable station



Fig 2321mdashStation antennas atWD4FAB Mounted are T-B M2 436-CP30 two stacked M2 23CM22EZmodified PrimeStar dish withhomebrew seven-turn Helix feedantenna The M2 2M-CP22 antenna is offthe bottom of the photo See Fig 2341for details of the center section

Fig 2322mdashICOMrsquosIC-910H a recententry into the multiband VHFUHFtransceiver worldhas an available 23-cm module

Fig 2323mdashThe YaesuFT-736R is a multi-mode transceiver for2 m (144-148 MHz)and 70 cm (430-450 MHz) It can beused for full-duplexreceiving and trans-mitting on Mode UVand VU An optional23-cm module covers1230-1300 MHz (ModeLU) Approximatepower output 20 Won 2 m and 70 cmand 10 W on 23 cm

Fig 2325mdashICOMrsquosIC-821H is anotherfull-featuredtransceiverdesigned forsatellite use

Fig 2324mdashKenwoodrsquos TS-2000is an all-band multi-mode transceiverthat covers HF 6 m2 m and 70 cm A23-cm (1240-1300 MHz)module is optionalTypical poweroutput is 35-45 W on144 MHz 30-40 W on430 MHz and 10 Won 1240 MHz

For the illustrated station the remotelymounted 23-cm amplifier (see ldquoDoubleBrick Amplifier Constructionrdquo) is containedin a tower-mounted-box The regulated dcpower requirements for this amplifier are oftoo high a current at 138 V-dc to bring it upfrom the ground as the voltage loss of anyreasonable cable would be excessive In-stead 24 V dc unregulated power is takenfrom the station power supply before itsregulator This power is brought up the towerand regulated to 138 V where it is neededThis power regulator is borrowed fromChapter 17 ldquo28-V High-Current PowerSupplyrdquo using only the regulator circuitryand adjusting the output voltage down to138 V dc

Much of your stationrsquos uplink perfor-mance strongly depends upon the satellitersquosantenna off-pointing or squint angle L-band and U-band receiving antennas areusually high-gain arrays with measuredgains of 16 dBic and 15 dBic respectivelyThis means that the antenna half-power-beamwidth (HPBW) of these arrays arerelatively narrow calculated to be HPBW= 285deg and 320deg respectively When asatellitersquos main axis (+Z axis) is offpointed from your ground station that off-pointing angle is known as the squintangle If the squint angle is less than halfof the HPBW the ground station will bewithin the spacecraft antenna nominalbeam width It is one of the informationoutputs from most of the newer computersatellite tracking programs With theweaker signals from birds at higher alti-tudes the effects of the squint angle are

more pronounced making the HPBW val-ues sometimes seem even smaller

SOME L-BAND PROBLEMSAND SOLUTIONS

An examination of an efficient operat-ing system must include all of the various

parts of that system and how they best fittogether The trick is in turning negativesinto positives as shown by K9EK For L-band transmitting the problems are morephysical than electronic Fig 2326 illus-trates this approach

First is the fact that transmitters and


2312 Chapter 23

Fig 2326mdashL-Band Transmitting anintegrated approach

Table 233 ndash Suppliers of Equipment of Interest to Satellite Operators

Multimode VHF and UHF Transceiversand Specialty Equipment

ICOM AmericaKenwood CommunicationsYaesu USA

Converters Transverters andPreamplifiers

Advanced Receiver ResearchAngle LinearDown East MicrowaveHamtronicsHenry RadioThe PX ShackParabolic ABRadio KitRF ConceptsSpectrum InternationalSSB Electronic

Power Amplifiers

Alinco ElectronicsCommunications ConceptsDown East MicrowaveEncommFalcon CommunicationsMirage CommunicationsParabolic ABRF ConceptsSSB ElectronicsTE Systems

Antennas

Cushcraft CorpDown East MicrowaveKLM ElectronicsM2 Antenna SystemsParabolic ABTelex Communications

Rotators

AllianceDaiwaElectronic Equipment BankKenproM2 Antenna SystemsTelexYaesu USA

Other Suppliers

AEAATV ResearchDown East MicrowaveElectronic Equipment BankGrove EnterprisesM2 Antenna SystemsMicrowave Components of MichiganPacCommSHF Microwave PartsTucson Amateur Packet Radio (TAPR)

antennas are usually in separate places witha long length of coaxial cable connectingthe transmitter to the antenna Coaxial cableis an imperfect RF conductor and withlosses increasing with frequency and lengthof cable Common (and reasonably priced)coaxial cables have unwanted losses at1270 MHz The old standby RG-8U losesalmost 13 dB per 100 feet at 1270 MHz A100-foot feedline would only have 05 Wcoming out from 10 W going in Of coursewe could increase transmitter power by 20times to compensate but those are quiteexpensive watts to be used for heating co-axial cable Coaxial cable ldquohardlinerdquo is agood but an expensive solution and even ithas significant loss Low-loss L-bandwaveguide is much too large and expensiveto be considered

What is needed are methods of getting allof the transmitter power to the antenna Youmay not want to remotely mount your en-tire L-band transmitter at the antenna al-though some manufacturers are offeringtransmitting converters for that service Amuch better solution would be to split thetransmit power generation into two stagesand integrate the antenna and final ampli-fier stage by mounting a final amplifier verynear the antenna feedpoint This will greatlyreduce the transmitter to antenna feed-line

loss by eliminating most of the feed lineFortunately an elegant solution exists forthe ldquofinal amplifier stagerdquo of this integra-tion This is the M57762 hybrid linear am-plifier module This 1-W input 10-18 Woutput ldquobrickrdquo has 50-Ω input and outputimpedance and requires only the additionof connectors a heat sink and simple dcpower circuitry A second design of ampli-fier is also offered using two of theseM57762 modules for higher output power

There is still the problem of the feed-line loss between the shack transmitterand the final amplifier stage but there areways to use this to an advantage Most L-band transmitters use the M57762 brickas part of their output stage and are ratedfor 10 W (+40 dBm) RF output The re-motely mounted final amplifier stage re-quires only 1 W (+30 dBm) RF input sosome method of reducing the transmitteroutput to match the amplifier input Avery satisfactory way to do this is to usethe loss qualities of a length of small co-axial cable as an attenuator For this feeda 10-dB loss between the transmitter andamplifier is needed Referring to cablemanufacturerrsquos data a length of coaxialcable can be determined that will give therequired 10-dB attenuation then use it toconnect the transmitter and amplifier

Note This is a partial list The ARRL does not endorse specific products



Fig 2328mdashJust a handful of parts are needed to connect the brick amplifiermodule All capacitor pairs are 10 μμμμμF35 V chip or tantalum units in parallel with1 nF chip capacitors D1 is a 4-A (minimum) 50-V power rectifier such asDigi-Key GI820CT-ND It prevents damage due to reverse connection of the powerleads U1 is a 7809 voltage regulator (9-V 1-A) Check RF Parts and Down EastMicrowave for pricing and availability of the amplifier module

Fig 2329mdashThis is an alternate morepowerful design of the L-band brickamplifier This is a pair of heat sinksmounted face to face with a dc motorcooling fan the electronics aremounted on each side with thecombiner and relay circuitry on thenear side From left to right output3-dB hybrid coupler directional couplerfor power measurement the four-portrelay and the input 3-dB hybridcoupler

DOUBLE BRICK L-BAND AMPLIFIERThis second L-band amplifier is more

complex offering considerably more out-put power (asymp40 W) and was originallyconstructed for terrestrial 1296-MHz ser-vice by WD4FAB This amplifier alsooperates in class AB linear As the ampli-fier is pretty broad-banded it can servethe satellite service as well as for the origi-nal terrestrial service plans all is the mat-ter of not pointing your antenna intothe sky for that 1296-MHz contact Theinspirational credit for using the M57762module and getting this unit started isgiven to the North Texas Microwave Soci-ety NTMS has a lot of good ideas flowingthrough their newsletters

Fig 2329 shows this completed assem-bly as it was just removed from the towerbox for the purpose of the picture takingThis assembly is composed of two flangedextruded heat sinks mounted face-to-facewith the brushless dc blower moving cool-

Fig 2327mdashThe matching brick amplifiercan be mounted on the counterbalanceside of the Helix antenna boom

SINGLE BRICK L-BAND AMPLIFIER

The amplifier of Fig 2327 was con-structed by K9EK by mounting the M57762module directly to a heat sink (no insulatorrequired but thermal compound is highlyrecommended) then using an etched cir-cuit board slipped under the leads of themodule to provide both RF and dc connec-tions The schematic for this amplifier isshown in Fig 2328 The board is made from0062-inch thick G10 board Keep the in-put and output lines 010-inch wide to main-

tain the 50-Ω input and output impedanceThe type N connectors should be mountedon the end of the heat sink in such a mannerthat the center conductors lie directly onthe board traces Ensure that the circuitboard is well grounded to the heat sink bydrilling and tapping several holes throughthe circuit board as shown

This amplifier operates in class AB lin-ear and therefore draws some (about

ing air through the finned chamber of theheat sinks The identical M57762 moduleldquobrickrdquo amplifiers and their bias circuitryPCB assemblies are mounted on thetroughs of each heat sink on the oppositesides of the assembly

Fig 2330 and Fig 2331 provide theschematic information for this amplifierassembly The following notes will givethe constructor details that may not beobvious from the photographs and sche-matics Considerable care is needed inmaking the RF connections between thesemodule amplifiers and their respectiveinput and output 3-dB hybrid couplersSlight differences in getting really equallength lines here can make a large differ-ence in the overall performance Notice inFig 2329 that the input coaxial lines onthe right are of flexible Teflon 50-Ω cablewhile the output lines on the left are ofthe semi-rigid UT141 copper jacketed co-

400 mA) dc current when not transmittingIt was decided that the additional circuitcomplexity to cut the amplifier off com-pletely was not warranted You just turn offthe dc supply during long standby periodsThe full load current is approximately 4A

A template with additional construc-tion details and a PC board layout is avail-able from the ARRL See the HandbookCD-ROM Templates section for details


2314 Chapter 23

axial cable selected because of the higherpower level at this point Each end of theUT141 cables is terminated in an SMAconnector for ease of handling and uni-formity of cable length

Also shown along the facing side of theheat sink assembly is a collection of RFparts which from left to right are outputhybrid coupler directional coupler forpower measurement the four-port relay

Fig 2331mdashSchematic diagram of bias circuitry for the L-band amplifier assembly

Fig 2330mdashSchematic diagram of the more powerful L-band amplifier assembly

and the input hybrid coupler Having afour-port relay of this type surely makeslife easier as it handles both input andoutput switching The output from thedirectional coupler is converted to a dcsignal by a diode and capacitor right at theSMA connector (not shown) that mountsto the coupled port That dc signal is sentback to the station to give a very usefulindication of the output power Note also

the 50-Ω load terminations that are SMA-connector-mounted to the couplers Theseloads absorb any unbalanced power fromthe amplifiers through the hybrid couplersWhile the input coupler did not need sucha large load it was easier to buy two iden-tical loads

For the M57762 module assembliesFig 2332 there are a number of detailsthat are not so obvious some mechanicaland some electrical First is to note thatmeasures are taken to insure that the mod-ule is very thoroughly clamped to the heatsink through the use of a pair of 64-mm(025-inch) square brass bars Usingscrews alone would provide insufficientclamping forces The module must haveheat sink compound used between it andthe heat sink and that interface must besmooth and flat for reasonably decent heattransfer These bars are elongated to serveadditional purposes as the bar at the outputend of the module (at the right) has a two-hole SMA connector embedded in it so asto get a very close termination to the wirelead of the RF output of the module Thisbar also serves as a low-resistance dc con-nection for the power ground lead to themodule thereby not depending upon acasual connection through mountingscrews and the heat sink For the input endthe coaxial cable is fed through a hole inthe bar (at the left) to also get the closeconnection to the module RF input Notethe short exposed RF leads at these points

There are three other wire leads to themodule two for +138 V and one for the+9 V bias power These leads are individu-ally filtered with FB43101 ferrite beadsand with the leads running across the top ofa 1nF trapezoidal filter capacitor solderedto the PCB The PCB is a double-sided G10



Fig 2333mdashA close-up view of one ofthe 3-dB hybrid coupler assemblies(the two are identical) showing itsconstruction using Sage Wirelineregsbquofour 2-hole SMA connectors spacersand screw hardware Note the 50-ΩΩΩΩΩterminated port Fig 2334mdashDetails of the construction of the 3-dB hybrid coupler assemblies

Fig 2332mdashOne side of the amplifier assembly showing the brick amplifier and theone-sided PC board with bias regulator and filter circuitry Note that the input andoutput coaxial cables are soldered to the brass clamp bars so that the centerconductor is closely ldquopresentedrdquo to the input and output terminations of the brickamplifier

board 0062-inches thick with only thetopside formed into circuit patterns Thereverse side of the PCB is only used as theground plane for the power circuits Thetwo sides of the PCB are connected withcopper or brass foil wrapped around theedges at selected locations

This bias circuitry operates to shut offthe bias to the module when not transmit-ting through a conventional grounding-on-PTT control line that comes up fromthe station This same line which is con-trolled by a sequencer in the station alsooperates the four-port TR relay It wasdetermined necessary to turn off the mod-ule to prohibit it from having any possibleemissions while the station is in its most

sensitive receiving condition althoughthis is unproven

Operation of the bias circuitry is throughthe diode isolated control line shutting offthe bias to a saturated 2N2222 which inturn unclamps the LM317 regulator refer-ence lead It is interesting what tricks can

be done with these adjustable regulatorsAll of the additional capacitive filteringneeded for the regulator is added

One of the two identical 3-dB hybridcoupler assemblies is shown in Fig 2333with drawing details shown in Fig 2334The neat tricks of constructing these cou-plers using the Sage Wireline and SMAconnectors was learned from KE3D whoprobably ldquoborrowedrdquo it from S57MVProper wiring of the Wireline to the SMAconnectors is very important here as ishaving equal lengths of equal-propertiescoaxial lines from the amplifiers to thecouplers Careful attention to small detailshere pay great dividends in performanceAlso note the ldquoreversalrdquo of the input linesfrom the coupler to the amplifiers neededto compensate for 90deg phase shifts of thehybrids Without this input crossoverthere would be no RF output The first as-sembly of this unit had ignored that phaseshift and the amplifier input lines had to beldquopatchedrdquo with extension cables to correctfor that bit of forgetfulness

Templates with additional constructiondetails and PC board layouts are availablefor each of these two amplifiers on the CDincluded with this book

RECEIVING PREAMPLIFIERS ANDRECEIVE CONVERTERS

Receiving Phase-3E downlinks willrequire equipment for the microwavebands Operating experience with AO-40


2316 Chapter 23

Fig 2336mdashThis SSB Electronic unit(left) is one of several solutions formast-mounted S-band receiveconverters Other manufacturersincluding Down East Microwave (top)have similar offerings

Fig 2337mdashDetails ofWD4FABrsquos towercluster of satelliteantennas including ahome-brew elevationrotator Top tobottom M2 436-CP30a CP U-band antennatwo each M2

23CM22EZA antennasshown in a CP arrayfor L band ldquoFABStarrdquodish antenna withhelix feed for S bandM2 2M-CP22 a CPV-band antenna (onlypartially shown) Toleft of dish antenna isa NEMA4 equipmentbox with an internal40W L-band amplifierand also hostsexternally-mountedpreamplifiers

has shown that receiving antenna gainsneed to be 22 dBic minimum On S bandthis has clearly been shown to requirethe use of a dish antenna with at least adiameter of 600 mm As there are no com-mercial base-station S band receiversoutboard S band down-converters need tobe used and have become available in re-cent years with a lot of interest in soak-ing up the surplus market units providedby Drake and others Fig 2335 Commer-cial Amateur S band receive convertershave been coming on the market fromSSB-USA with their UEK-3000SATfrom Down East Microwave (DEM) withtheir 2400-144RX and 2400-432RX (seeFig 2336) from Parabolic AB with theirldquoMode S Down-converterrdquo and fromother sources Amateur microwave op-eration is not a ldquostrangerdquo activity rele-gated just to the specialists anymore assatellite enthusiasts have been exploringthese S band downlinks for some time andmanufacturers have responded by in-creasing the supply of useable equipmentfor S band

No discussion of satellite receiving sys-tems would be complete without mention-ing preamplifiers and their location Themast mounting of sensitive electronicequipment has been a fact of life for theserious VHFUHF operator for yearsalthough it may seem to be a strange ordifficult technology for HF operatorsWhile a preamplifier can be added at thereceiver in the station it will do nogood there Vastly better results will beobtained if the preamp is mounted directlyto the antenna To get the most out of yourVHFUHF satellite station yoursquoll need tomount a low-noise preamplifier or receive

Fig 2335mdashS-band converter that wasavailable from Drake and easilymodified for satellite service

receiver noise figure Antenna mountingthe preamplifier or down-converter willovercome these noise figure problems ForS band placing either a preamp or the re-ceiving down-converter on your antennafeed point is essential Not even mastmounting the preamplifier will sufficehere

Low-noise front ends for down-convert-ers or preamps are essential for receivingweak satellite signals especially as theoperating frequency goes higher Multi-mode rigs and most down-converters willhear much better with the addition of apreamplifier employing GaAs FET orPHEMT technology ahead of the front endalbeit at the expense of the reduction in thethird-order intercept point of the receiverDEM provides a weather-resistant assem-bly in their 13ULNA unit See photos ofS-band dish antennas for views of thisDEM product Other very qualified pream-plifier units are available from SSB-USA

Table 233 lists other sources of com-mercially built preamplifiers and receiveconverters for most all VHF UHF andmicrowave bands These are available inseveral configurations Many models aredesigned for mounting in a receive-onlyline for use with a receiving converteror transverter Others designed withmultimode transceivers in mind havebuilt-in relays and circuitry that automati-cally switch the preamplifier or converterout of the antenna line during transmitMost of these models are housed withrelays in weatherproof enclosures thatmount right at the antenna For the equip-ment builder several suitable designsappear in The Radio Amateurrsquos SatelliteHandbook

converter on the tower or mast near theantenna see Fig 2337 so that feed-linelosses do not degrade low-noise perfor-mance Feed-line losses ahead of thepreamplifier or converter add directly to



ACCESSORIESReceiver audio output noise on these

higher satellite bands is often quite dis-turbing to many operators taking awayfrom the ldquolistenablityrdquo or the ldquoarm chairrdquoquality of the QSO audio on these bandsSome of this disruption can also be fromthe in-band use of such equipment as mi-crowave ovens and the modern spread-spectrum 24-GHz cordless telephonesthat are becoming common in our house-holds Modern receivers and accessoryequipment comes to the rescue here and isthe reason for the use of the HF transceiver(an IC-746) in receiving the S-band sig-nals of the station shown in Fig 2320Newer model HF transceivers provide IFDSP and other features that provide veryuseable ldquoNoise Reductionrdquo and ldquoNoiseBlankerrdquo functions The noise blanker inparticular removed all the observed noisefrom a 24-GHz Spread-Spectrum cordlesstelephone near the illustrated station evenwith the very high sensitivity of the S-bandreceiving equipment In the illustrated sta-tion an outboard audio DSP unit (aTimewave DSP599zx) is very helpful toremove the audio ldquoRandom Noiserdquo that isnot removed by the IF DSP The combina-tion of the equipment shown does provideldquoarm-chairrdquo quality comfortable listeningSome of the other most recently availableAmateur transceivers may incorporateboth the audio and IF DSP noted abovepossibly eliminating the need for an out-board audio DSP unit

Great caution by the operator must beexhibited when using a transceiver for re-ceiving the S-band signals as even theslightest inadvertent moment of transmit-ter operation into the ldquorear endrdquo of a down-converter can make it an instant hot dogwithout a roll SSBUSA offers a protec-tion unit ldquoThe Protectorrdquo with a SSBpower rating of 50 W In the illustratedstation with its IC-746 transceiver the2-m receive line was internally isolatedfrom the transmitting circuits and broughtout to a SMA connector at a convenientpoint on the rear panel This separatedreceive capability on 2 m has saved thedown-converter on several occasions

One very helpful accessory for the sta-tion is the remote measurement of RFpower Such power meters are commer-cially available or easily constructed bythe handy operator This type of measure-ment is very meaningful for stations withlong feed lines between the transmitter andthe antennas making the determination ofEIRP more realistic The illustrated sta-tion uses a moving-coil power meter ofuncertain origin coupled with surplus orhome made directional couplers for powersampling near the antennas in the equip-

Fig 2338mdashKLM 2M-22C antenna CP switching relay with relocated balunProtective cover is needed for rain protection see text

ment box on the towerOperators unfamiliar with microwave

S-band operation may gain a greater con-fidence of their receivers with the additionof a 2101-MHz signal source Such signalsources have been in the literature in re-cent years and Down East Microwaveoffers a kit An S-band signal source canalso provide the user a convenient checkfor the station antennas and also as a cali-brator for the S-band receiver S meter

For stations using ldquocrossedrdquo Yagiantennas for CP operation one feature thathas been quite helpful for communicatingthrough most of the LEO satellites hasbeen the ability to switch polarizationfrom RHCP to LHCP In some satelliteoperation this switchable CP ability hasbeen essential

The station shown has an all up capabil-ity for analog and digital satellite opera-tions Not shown just to the left of thephoto is the station computer which pro-vides the satellite tracking informationfrom the Northern Lights Software Asso-ciation NLSA Nova for Windows track-ing program This provides output for theTAPR EasyTrak antenna controller aswell as providing the interface to the digi-tal communications operations using aPacComm SPIRIT-2 Packet ControllerPlease note the warning sign in Fig 2320as it is right and proper for the unwary atthat station

EXPOSED ANTENNA RELAYS ANDPREAMPLIFIERS

Experience with the exposed circularityswitching relays and preamplifiers mounted

on antennas have shown that they are proneto failure caused by an elusive mechanismknown as ldquodiurnal pumpingrdquo Often theserelays are covered with a plastic case andthe seam between the case and PC board issealed with a silicone sealant Preampsmay also have a gasket seal for the coverwhile the connectors can easily leak airNone of these methods create a true her-metic seal and as a result the daynighttemperature swings pump air and mois-ture in and out of the relay or preamp caseUnder the right conditions of temperatureand moisture content moisture from theair will condense inside the case when theoutside air cools down Condensed waterbuilds up inside the case promoting ex-tensive corrosion and unwanted electricalconduction seriously degrading compo-nent performance in a short time

A solution for those antennas withldquosealedrdquo plastic relays such as the KLMCX series you can avoid problems by mak-ing the modifications shown in Fig 2338Relocate the 41 balun as shown and placea clear polystyrene plastic refrigeratorcontainer over the relay Notch the con-tainer edges for the driven element and theboom so the container will sit down overthe relay sheltering it from the elementsBond the container in place with a few dabsof RTV adhesive sealant Position theantenna in an ldquoXrdquo orientation so neitherset of elements is parallel to the groundThe switcher board should now be cantedat an angle and one side of the relay caseshould be lower than the other An ex-ample for the protective cover for anS-band preamp can be seen in the discus-


2318 Chapter 23

Fig 2341mdashVE5FP has a solution for hisAz-El rotators by bolting two of themtogether in his ldquoAn Inexpensive Az-ElRotator Systemrdquo QST December 1998

sion on feeds for parabolic antennasFor both the relay and preamp cases

carefully drill a 332-inch hole through thelow side of the case to provide the neededvent The added cover keeps rain water offthe relay and preamp and the holes willprevent any build-up of condensationinside the relay case Relays and pream-plifiers so treated have remained clean andoperational over periods of years withoutproblems

Another example for the protection ofremotely tower mounted equipment isshown in Fig 2337 illustrating the equip-ment box and ldquomast mountedrdquo preamplifi-ers at the top of WD4FABrsquos tower Thecommercial NEMA4 rated equipment boxis used to protect the 23-cm power ampli-fier and its power supply as well as amultitude of electrical connections Thissteel box is very weather resistant with anexceptionally good epoxy finish but itis not sealed and so it will not trap mois-ture to be condensed with temperaturechanges Be sure to use a box with at leasta NEMA3 rating for rainwater and dustprotection The NEMA4 rating is just alittle better protection than the NEMA3rating Using a well-rated equipment boxis very well worth the expense of the boxThe box also provides some pretty goodflanges to mount the ldquomast-mountedrdquopreamplifiers for three bands This box isan elegant solution for the simple need of

rain shelter for your equipment as illus-trated in Fig 2339

ELEVATION CONTROLSatellite antennas need to have eleva-

tion control to point up to the sky the ldquoElrdquopart of the needed Az-El control of satel-lite antennas Generally elevation boomsfor CP satellite antennas need to be non-conducting so that the boom does not af-fect the radiation pattern of the antenna Inthe example shown the elevation boomcenter section is a piece of extra heavywall 112-inch pipe (for greater strength)coupled with a tubular fiberglass-epoxyboom extension on the 70-cm end and ahome-brew long extension (not shown inthe photo) on the 2-m end using large PVCpipe reinforced with four braces ofPhillystran non-metallic guy cable (PVCpipe is notoriously flexible but thePhillystran cables make a quite stiff andstrong boom of the PVC pipe) For smallerinstallations a continuous piece of fiber-glass-epoxy boom can be placed directlythrough the elevation rotator

Elevation boom motion needs to bepowered and one solution Fig 2340 usesa surplus jackscrew drive mechanism Oneoperator VE5FP found a solution for hisAz-El needs by using two low-cost light-weight TV rotators1 See Fig 2341

Operators through the years have em-ployed many methods for the control oftheir antenna positions ranging from trueldquoarm-strongrdquo manual positioning tomanual operation of the powered antennaazimuth and elevation rotators and to fullyautomated computer control of the rota-tors While computer control of the rota-tors is not essential life is greatly assistedwith the use of your computer Fully auto-mated control of your rotators is possiblefor such tasks as digital message upload-ing and downloading For many years oneof the keystone control units for rotatorshas been the Kansas City Tracker (KCT)board installed in your computer Mostsatellite tracking programs can connect tothe KCT with ease There are other op-tions these days to replace the KCT unit

A recent trend for amateur antenna con-trol has been evolving however in theform of a standalone controller that trans-lates computer antenna position informa-tion into controller commands with anunderstanding of antenna position limitsThese boxes represented by the newEasyTrak unit Fig 2342 from the TucsonAmateur Packet Radio (TAPR) grouphave made this capability readily avail-able for many amateurs One of theEasyTrak units is also shown in Fig 2320The station computer to the left and out ofthe photo is used to upload antenna posi-

Fig 2340mdashWD4FABrsquos home-brewelevation rotator drive using a surplusstore drive screw mechanism

Fig 2339mdashProtection for tower-mounted equipment need not beelaborate Be sure to dress the cablesas shown so that water drips off thecable jacket before it reaches theenclosure

tions to EasyTrak The computer can alsocontrol the operation of your station trans-ceiver through the radio interface providedin EasyTrak you will not need any otherradio interface

ANTENNASAntennas have always been favorite

subjects for amateur operators Everyone



Fig 2343mdashThis L-band helix antenna was designed to behome-brewed without any special tools or shop equipmentIt is mounted on a 4-foot-long fiberglass tube

Fig 2342mdashThe EasyTrak automated antenna rotator andradio controller by TAPR

is an expert Fig 2321 shows the exampleof the antennas for one station The Yagiantennas are used for the U and L-banduplinks while the S-band dish antenna isfor the downlink These satellite antennasare tower mounted at 63 feet to avoidpointing into the many nearby trees andsuffering from the ldquogreen attenuationrdquoprovided by those trees Satellite antennasotherwise do not need to be mounted sohigh If the satellite antennas are mountedlower down the reduced feed-line lengthand losses are a great benefit

Linearly polarized antennas are ldquohori-zontalrdquo or ldquoverticalrdquo in terms of theantennarsquos position relative to the surface ofthe Earth a reference that loses its meaningin space The need to use circularly polar-ized (CP) antennas for space communica-tions is well established as in space there isno ldquohorizontalrdquo or ldquoverticalrdquo but there isright-hand and left-hand circular polariza-tion CP With CP the wavefront describesa rotational path about its central axiseither clockwise (right-hand or RHCP) orcounter clockwise (left-hand or LHCP) Ifspacecraft antennas used linear polariza-tion ground stations would not be able tomaintain polarization alignment with thespacecraft because of changing orientationGround stations using CP antennas are not(generally) sensitive to the polarizationmotions of the spacecraft antenna andtherefore will maintain a better communi-cations link

UPLINK ANTENNASExperience with AO-40 has clearly

shown the advantages of using RHCPantennas for both the uplink and downlinkcommunications The antennas shown inFig 2321 are a single-boom RHCP Yagiantenna for U band a pair of closelyspaced Yagi antennas phased for RHCPfor L band and a helix-fed dish antennafor S band The antenna gain requirements

for U band can easily be met with a30-element ldquocrossed Yagirdquo two 15 ele-ment Yagi antennas mounted on a singleboom with one placed a 14 wavelengthforward of the other This arrangementallows for an uncomplicated phasing har-ness to couple the two antennas together toa single feedpoint Antennas of this sizehave boom lengths of 4 to 412 wave-lengths The enterprising constructor canbuild a Yagi antenna from one of severalreferences such as The ARRL AntennaBook or he might construct a 16 to 20 turnhelix antenna for this service Most of usmight prefer however to purchase such awell-tested antenna from such commercialsources as M2 or HyGain In the past KLM(now out of business) had offered a 40 ele-ment CP Yagi for U band satellite serviceand many of these are still in satisfactoryuse today

L-band uplink antennas become evenmore manageable as their size for a givengain is only one-third of those for U bandAlternatively higher gains can be ob-tained for the same boom lengths Withthis band there is a narrower differencebetween using a dish antenna and a Yagior helix as a 21 dBic dish antenna wouldhave a 12-m (4 foot) diameter Some ofus cannot afford such ldquoreal estaterdquo on ourelevation rotators and seek the lowerwind-loading solutions offered by Yagiantennas Long-boom rod-element Yagior loop-Yagi antennas are commerciallyoffered by M2 and DEM although thisband is about the highest for practicalYagi antennas The example shown in Fig2321 is a pair of rod-element Yagi anten-nas from M2 in a robust arrangementThese antennas provide an overall gain ofabout 215 dBi If greater L-band poweris available than the 40 W shown in theillustrated station the constructor maywant to consider the helix antenna thatfollows

L-BAND HELIX ANTENNACONSTRUCTION

Fig 2343 shows an easy-to-buildantenna and support structure provided byK9EK Fiberglass tubing was used for thisstructure as it has better outdoor longev-ity Mounting of a helix of this naturerequires that it be placed out ldquoin frontrdquo ofthe elevation boom so that there are nounwanted structures in the RF field of theantenna This places a need for the counterweighting of the antenna to remove theunbalanced loading and strain on theelevation rotator The constructor shouldtake these provisions and should considerthe possible placement of the outputamplifier as part of that counterweightthus also making for a very short low-lossfeed line to the antenna

Probably the easiest way to construct ahelix antenna is to mark the wire thenclose wind the spiral on a form thenstretch the winding out to match therequired diameter and turns spacing Firstlay out the required length of 6 AWG barecopper wire (available as ground wirewherever house wiring is sold) Tostraighten it clamp one end in a vise thensqueeze the wire between two wood blocksand pull the blocks along the wire Oncethe wire is straight and even clearly markthe wire at each ldquocumulative wire lengthrdquodimension as shown in Fig 2344 Thesemarks show identical length per turn andthey should line up along the completedhelix Allow 1-2 feet to remain on eitherend of the wire for handling which will becut off after construction Cumulativelength is used to prevent the compoundingof measurement errors

Then close wind the wire smoothly andtightly around a piece of 212-inch pipe(measures φ2875 inch) with the lengthmarks outward The wire will spring backsome after winding so using two people tohelp pull to keep the winding tight gener-


2320 Chapter 23

Fig 2345mdashMore construction details of L-band helix antenna

ally works better You must wind the he-lical element in a right-hand direction(clockwise) look at a standard machinescrew or bolt and have the turns proceed inthe same direction Then hang the wire coilover a horizontal tube or form (the samePVC pipe used for winding will do well)that has been marked every 231 inchesDo this cumulatively to prevent errorsHolding the end turns (which will eventu-ally be cut off) of the wire coil gentlystretch the helical element to the appropri-ate turn-to-turn spacing Ensure that theturn-marks on the wire remain lined upyou may have to gently wind or unwindthe helical element as you go You canmake a 215-inch (less your wire size)spacer to drop between turns to aid in get-ting the spacing correct

Finally cut off the excess wire on theinput end of the helical element Leave theopposite end uncut so if you goof on theinput end you can simply cut the error offand try again After the antenna is com-pleted go back and cut off the excess fromthe far end To connect the input end of thewire to the input connector flatten the last14-inch of the input end of the wire withlocking grip pliers or a hammer and steelblock Once it is flat and even drill a holein the end of the wire to slip over the centerpin on an N connector

The theoretical impedance of a helixantenna fed from the periphery is 140 Ω

Fig 2344mdashConstruction details of L-band helix antenna

A clever method of changing this to 50 Ωis by the addition of a λ4 impedancetransformer to the first quarter turn of thehelical element wire itself It has beenfound empirically that a 050-inch-widestrip of 0010-inch-thick sheet brassmakes a satisfactory impedance match-ing device Cut the brass strip as shown inthe figure The strip is soldered to the firstquarter turn of the helical element wirestarting 025 inch from the connectordrilling The underside of the strip mustbe flat relative to the reflector disc Sil-ver-bearing lead-free plumbing solder isbetter than standard lead-tin solder and ishighly recommended

The method of helix antenna construc-tion involves a single central length of10 inch diameter fiberglass tubing withthe helical element supported on 0375-inch diameter fiberglass standoff rods ortubes Fig 2345 shows the dimensions andconstruction for this helix antenna Care-fully attach the helix support rods to thecentral boom as shown Mount a 7 inch to914-inch diameter (075λ to 1λ) reflectorplate to the frame with homemade anglebrackets The helical element is slippedover the boom and stretched onto the sup-port rods and held to the rods with wireties A homemade clamp plate and U-boltsare used to connect central rod to theantenna elevation boom

After attaching the helical element onto

the support frame solder the hole in theend of the first turn to the input connectoran N connector mounted from the back ofthe reflector plate Position the impedancematching strip at 010-inch (25mm) spac-ing from the reflector plate and solder it inplace Then secure the helical element inplace On two samples of the antennashown the input return loss was measuredin excess of ndash16 dB (SWR=1381) Ifproper equipment is available lowerreturn loss and SWR values can beachieved with this tuning system

A practical shortcoming of the axialmode helix antenna is not obvious Theentire helical element itself is a singlelong piece of copper wire connected tothe input connector Since this wire isphysically isolated from dc ground atmo-spheric static electricity may build up onthe element until it damages the attachedsolid-state device So some method isneeded to dc ground the helical elementitself without seriously interfering withthe RF characteristics of the antenna Onemethod of preventing static buildup is toadd a shorted λ4 stub to the antenna feedA shorted quarter-wave stub presentsextremely high RF impedance at its non-shorted end making it virtually invisibleto RF energy at its design frequency Atthe same time it provides a dc short toground for the helical element itselfeffectively draining off static electricity



Fig 2348mdashK5GNArsquosldquocircularizedrdquo meshmodification of anMMDS dish antennawith helix CP feedand DEM preamp

Fig 2346mdashAnother commerciallyavailable solution for S-band receptionuses this TVRO antenna

Fig 2347mdashK5OErsquos mesh modificationof a MMDS dish antenna with helix CPfeed and DEM preamp

before it can build up This shorted stubcan be made from a T connector andcoaxial cable The length of the stub (mea-sured from the center of the main cable tothe short itself) must be calculated andmust include the VF (velocity factor) ofthe cable being used Note that an actualλ4 stub is too short to be physically real-izable and a λ2 must be added to the cableto create a 3λ4 stub With RG-213 cable(VF = 066) the total length of the 3λ4stub is 460 inches This stub has beenshown to have almost no effect on antennaperformance at the design frequency

PARABOLIC REFLECTORANTENNAS FOR S BAND

The satellite S-band downlinks havebecome very popular for a variety of rea-sons Among the reasons are goodperformance can be realized with a physi-cally small downlink antenna and goodquality down-converters and preamps areavailable at reasonable prices as previ-ously discussed Increased operation on Sband has long been advocated by a numberof people including Bill McCaa KOslashRZwho led the team that designed and builtthe AO-13 S-band transponder2 and JamesMiller G3RUH who operated one of theAO-40 command stations3 Ed KromeK9EK and James Miller have publishedmany articles detailing the construction ofpreamps down-converters and antennasfor S band45678

WOslashLMD notes that like a bulb in a flash-light the parabolic reflector or dishantenna must have a feed source lookinginto the surface of the dish Some dishesare designed so that the feed source ismounted directly in front of the dish Thisis referred to as a center-fed dish Otherdishes are designed so that the feed sourceis off to one side referred to as an off-center fed dish or just offset-fed dish Theoffset-fed dish may be considered a sec-tion of a center-fed dish The center-feddish experiences some signal degradationdue to blockage of the feed system butthis is usually an insignificantly smallamount The offset-fed dish is initiallymore difficult to aim as the direction ofreception is not the center axis like thecenter-fed dishes The attitude of the off-set dish is more likely to be vertical mak-ing it less susceptible to loss from snowaccumulation Offset-fed dishes mayhave difficulty pointing horizontally forterrestrial communications One enter-prising ham W4WSR mounted his off-set-fed PrimeStar dish upside down whichmatched terrestrial pointing better Olderdishes tend to be center fed newer dishesare offset fed

The dishrsquos parabola can be designed so

the focus point is closer to the surface ofthe dish referred to a ldquoshort focal lengthrdquodish or further away from the dishrsquos sur-face referred to as a ldquolong focal lengthrdquodish To get the exact focal length mea-sure the diameter of the dish and the depthof the dish The diameter squared dividedby 16 times the depth is the focal lengthThe focal length divided by the diameterof the dish gives the focal ratio commonlyshown as fD Center-fed dishes are usu-ally short focal ratios in 03 to 035 rangesOffset-fed dishes are usually longer focallength such as 045 to 08 If you attach acouple of small mirrors (a couple of theYFrsquos eye shadow mirrors when she isnrsquotlooking) to the outer front surface of a dishand then point the dish at the Sun you willeasily find the focus point of the dish Putthe reflector of the patch or helix just be-yond this point of focus

An alternate method for finding a dishrsquosfocal length is suggested by W1GHZ andhe provides that calculation on his Website at wwww1ghzcx10g10g_homehtm This method literally measures asolid-surface dish by the dimensions of thebowl of water that it will form when prop-erly positioned

While many of us enjoy building our ownantennas some of these microwave anten-nas are so small that they donrsquot require atruck to transport them Surplus marketavailability of these small dish antennasmakes their construction unproductiveMany hams use the practices of AO-13 op-erators in using a surplus MMDS linearscreen parabolic reflector antenna Fig 2346These grid-dish antennas are often calledldquobarbeque dishesrdquo K5OE Fig 2347 andK5GNA Fig 2348 have been showing ushow to greatly improve these linearly polar-ized reflectors by adapting them for the CPservice See the K5OE site membersaolcomk5oe The work shown us by these op-erators illustrate that simple methods can beused to ldquocircularizerdquo a linear dish and to


2322 Chapter 23

further add to its gain by using simple meth-ods to increase the dish area and feed effi-ciency

Some smaller dishes are constructedfrom solid aluminum or steel Fig 2349shows one such 60-cm spun aluminum dishthat was designed by G3RUH and ON6UGThis kit complete with a CP patch feed isavailable from SSB-USA and has a gain of21 dBic and provides a 25-dB Sun noisesignal Sometimes fiberglass constructionis used with a conductive coating as shownin Fig 2350 Some operators are using theirlarge 10-foot TVRO dishes for Amateursatellite service although these types ofantennas cannot easily be mounted on atower to clear the nearby trees These largerdishes are generally made from perforatedsteel or aluminum Dishes with perforationsslightly reduce the wind loading If the per-forations are made smaller than λ10 the

Fig 2351mdashDetailof 60-cm S-banddish antenna withfeed

Fig 2349mdashG3RUHrsquos 60-cm spunaluminum dish with CP patch feedavailable as a kit

Fig 2350mdashPrimeStar offset-fed dishwith WD4FABrsquos helix-feed antennaNOslashNSV was so pleased with themodification that he renamed the dishldquoFABStarrdquo and made a new label

dish is equivalent to solid in terms of signalreflection At 2401 MHz (λ = 125 mm) thisis about 050 inch making standard 025-inch fence mesh a good option for a dishsurface with low wind loading

In the USA there are large numbers ofdishes that can be obtained either free or atlow cost But in some parts of the worlddishes are not so plentiful so hams maketheir own G3RUH shows us his exampleof creating a dish antenna see Fig 2351There are three parts to the dish antennamdashthe parabolic reflector the boom and thefeed There are as many ways to accom-plish the construction as there are con-structors It is not necessary to slavishlyreplicate every nuance of the design Theonly critical dimensions occur in the feedsystem When the construction is com-plete you will have a 60-cm diameterS-band dish antenna with a gain of about20 dBi with RHCP and a 3-dB beamwidthof 18deg Coupled with the proper down-con-verter performance will be more than ad-equate for S-band downlink

DISH FEEDSOn wwwult imatecharger com

WOslashLMD describes that the feeding of a dishhas two major factors that determine theefficiency Like a flashlight bulb the dishfeed source should evenly illuminate theentire dish and none of the feed energy

should spillover outside the dishrsquos reflectingsurface No feed system is perfect in illumi-nating a dish Losses affect the gain fromeither under-illuminating or over-illumi-nating the dish (spillover losses) Typicaldish efficiency is 50 percent Thatrsquos 3 dB oflost gain A great feed system for one dishcan be a real lemon on another dish A patchfeed system is very wide angle but a helixfeed system is narrow angle A short focalratio center-fed dish requires a wide anglefeed system to fully illuminate the dishmaking the CP patch the preferred feedsystem When used with an offset-fed disha patch-type feed system will result in aconsiderable spillover or over-illumina-tion loss with an increased sensitivity tooff-axis QRM due to the higher fD of thisdish Offset-fed dishes do much better whenfed with a longer helix antenna

A helix feed is simplicity personifiedMount a type N connector on a flat reflectorplate and solder a couple of turns wire to theinner terminal Designs are anywhere fromtwo to six turns The two-turn helices areused for very short focal length dishes inthe fD = 03 region and the six-turn heli-ces are used with longer focal length (fD ~06) dishes typically the offset-fed dishesSince AO-40 is right circular and the dishreflection will reverse the polarity the he-lix should be wound left circular lookingforward from the connector Helix feeds



Fig 2353mdashDetails of helix feed forS-band dish antennas The Type Nconnector is fixed with three screwsand is mounted on a 16-mm spacer tobring the PTFE molding flush with thereflector An easier mounting can beusing a smaller TNC connectorReflectors should be 95-100 mmcircular Dimensions are in mm 1 inch= 254 mm

Fig 2352mdashDetailsof CP patch feed forshort fD dishantennas by G3RUHand ON6UG

work poorly on the short focal length dishesbut really perform well on the longer focallength offset-fed dishes

A patch feed is almost as simple It istypically a type N connector on a flat re-flector plate with a tuned flat metal platesoldered to the inner terminal Sometimesthe flat plate is square sometimes it is rect-angular sometimes round It could havetwo feed points 90deg out of phase for cir-cular polarization as was used in theconstruction of the AO-40 U-band anten-nas Some patches are made rectangularwith clipped corners to add circularity On2401 MHz the plate is about 214-inchessquare and spaced from 116 inch to 14-inchaway from the reflector The point ofattachment is about halfway between the

PARABOLIC DISH ANTENNA CONSTRUCTION

center and the edge A round patch for2401 MHz is φ258 inches Patches workpoorly on the longer focal length offsetdishes but do very well on the shorter fo-cal length center-fed MMDS and TVROdishes A well studied CP patch feed for

these short fD dishes is shown to us byG3RUH in Fig 2353 and Fig 2352

For additional information on construct-ing antennas for use at microwave frequen-cies see The ARRL UHFMicrowaveExperimenterrsquos Manual

The following is a condensation of sev-eral articles written by G3RUH describinga dish antenna that can be easily built andused for reception of an S-band downlinkThe dish itself was previously describedand the article continues

The parabolic reflector used for theoriginal antenna was intended to be alampshade Several of these aluminumreflectors were located in department storesurplus The dish is 585 mm in diameterand 110 mm deep corresponding to an fDratio of 58511016 = 033 and a focallength of 033 times 585 = 194 mm The fD of033 is a bit too concave for a simple feedto give optimal performance but the pricewas right and the under-illuminationkeeps ground noise pickup to a minimumThe reflector already had a 40-mm hole inthe center with three 4-mm holes around itin a 25-mm radius circle

The boom passes through the center ofthe reflector and is made from 127-mmsquare aluminum tube The boom must belong enough to provide for mounting to therotator boom on the backside of the dishThe part of the boom extending through tothe front of the dish must be long enough tomount the feed at the focus If you chooseto mount the down-converter or a preampnear the feed some additional length willbe necessary Carefully check the require-ments for your particular equipment

A 3-mm thick piece of aluminum 65 mmin diameter is used to support the boom atthe center of the reflector Once the centermounting plate is installed the centerboom is attached using four small anglebrackets mdash two on each side of the reflec-tor See Fig 2351 for details of reflectorand boom assembly

A small helix is used for the S-bandantenna feed The reflector for the helix ismade from a 125-mm square piece of16-mm thick aluminum The center of thereflector has a 13-mm hole to accommo-date the square center boom describedabove The type N connector is mounted tothe reflector about 2125 mm from themiddle This distance from the middle isof course the radius of a helical antennafor S band Mount the N connector withspacers so that the back of the connector isflush with the reflector surface The helixfeed assembly is shown in Fig 2353

Copper wire about 32 mm in diameteris used to wind the helix Wind four turnsaround a 40-mm diameter form The turnsare wound counterclockwise This is be-cause the polarization sense is reversedfrom RHCP when reflected from the dishsurface The wire helix will spring outslightly when winding is complete

Once the helix is wound carefullystretch it so that the turns are spaced28 mm (plusmn1 mm) Make sure the finishedspacing of the turns is nice and even Cutoff the first half turn Carefully bend thefirst quarter turn about 10deg so it will beparallel to the reflector surface once thehelix is attached to the N connector Thisquarter turn will form part of the matchingsection

Cut a strip of brass 02-mm thick and6-mm wide matching the curvature of thefirst quarter turn of the helix by using apaper pattern Be careful to get this patternand subsequent brass cutting done exactlyright Using a large soldering iron andworking on a heatproof surface solder thebrass strip to the first 14 turn of the helixUnless you are experienced at this type ofsoldering getting the strip attached justright will require some practice If itdoesnrsquot turn out right just dismantle wipeclean and try again

After tack soldering the end of the helixto the type N connector the first 14 turnwith its brass strip in place should be 12mm above the reflector at its start (at the Nconnector) and 30 mm at its end Besure to line up the helix so its axis is per-pendicular to the reflector Cut off anyextra turns to make the finished helix have214 turns total Once you are satisfiedapply a generous amount of solder at the


2324 Chapter 23

Fig 2354mdashScreen display of W3PMrsquos spreadsheet evaluation of ground stationoperation with AO-40

Fig 2355mdashSeven-turn LHCP helix dishfeed antenna with DEM preamp

Fig 2356mdashMounting details of seven-turn helix and preamp

point the helix attaches to the N connectorRemember this is all that supports thehelix

Once the feed assembly is completedpass the boom through the middle hole andcomplete the mounting by any suitablemethod The middle of the helix should be

at the geometric focus of the dish In thefigures shown here the feed is connecteddirectly to the down-converter and thenthe down-converter is attached to theboom You may require a slightly differ-ent configuration depending on whetheryou are attaching a down-converter

preamp or just a cable with connectorAngle brackets may be used to secure thefeed to the boom in a manner similar to theboom-to-reflector mounting Be sureto use some method of waterproofing ifneeded for your preamp andor down-converter

HELIX FEED FOR AN OFFSET DISH ANTENNAThe surplus PrimeStar offset fed dish

antenna with its seven-turn helix feedantenna Fig 2350 is described in thissection When the feed antenna is directlycoupled with a preampdown-convertersystem this antenna provides superbreception of S-band signals with the satel-lite transponder noise floor oftenbeing the noise-limiting factor in thedownlink This performance is as had beenpredicted by the W3PM spreadsheetanalysis Fig 2354 and actual operatingexperience Operating experience alsodemonstrates that this antenna can receivethe Sun noise 5 dB above the sky noiseDonrsquot try to receive the Sun noise with theantenna looking near the horizon as ter-restrial noise will be greater than 5 dBat least in a big-city environment Theoperator NOslashNSV who provided this dishwas rewarded for his effort with a secondfeed antenna and he in turn provided newlabels for the dish titling it ldquoFABStarrdquo

The reflector of this dish is a bit out ofthe ordinary with a horizontal ellipseshape It is still a single paraboloid that

was illuminated with an unusual feedhornAt 2401 MHz we must be satisfied with amore conventional feed arrangement Achoice must be made to under-illuminatethe sides of the dish while properly feed-ing the central section or over-illuminat-ing the center while properly feeding thesides For the application shown here theformer choice was made The W1GHZwater-bowl measurements showed this tobe a dish with a focal point of f = 5006 mmand requiring a feed for an fD = 079 Thetotal illumination angle of the feed is 698degin the vertical direction and a feedhornwith a 3-dB beamwidth of 403deg At 50percent efficiency this antenna was calcu-lated to provide a gain of 219 dBi Aseven-turn helix feed antenna was esti-mated to provide the needed characteris-tics for this dish and is shown in Fig 2355

The helix is basically constructed asdescribed for the G3RUH parabolic dishnoted above A matching section for thefirst λ4 turn of the helix is spaced fromthe reflector at 2 mm at the start and 8 mmat the end of that fractional turn Modifi-

cations of the design include the use of acup reflector For the reflector a 2-mmthick circular plate is cut for a φ94 mm(075λ) with a thin aluminum sheet metalcup formed with a depth of 47 mm Em-ployment of the cup enhances the perfor-mance of the reflector for a dish feed

The important information for thisseven-turn helix antenna is Boom 127mm square tube or ldquoCrdquo channel Elementφ18-inch copper wire or tubing Closewind element on a φ150-inch tube or rodFinished winding is φ40 mm spaced to ahelical angle of 123deg or 28-mm spacingThese dimensions work out to have theelement centerline to be of a cylindricalcircumference of 10λ

When WD4FAB tackled this antennahe felt that the small amount of helicalelement support that James Miller usedwas inadequate in view of the real life



bird traffic on the antennas at his QTH Hechose to use PTFE (Teflonrdquo) support postsat every 12 turn This closer spacing ofposts also permitted a careful control ofthe helix winding diameter and spacingmaking this antenna very robust A fixturewas set up on the drill press to uniformlypredrill the holes for the element spacersand boom Attachment of the reflector isthrough three very small aluminum anglebrackets on the element side of the boom

Mounting of the helix to the dishrequires modification of the dishrsquos re-ceiver mounting boom Fig 2356 showsthese modifications using a machinedmount NM2A has constructed one ofthese antennas and shown that a machineshop is not needed for this constructionHe has made a ldquoZrdquo shaped mount fromaluminum angle plate and then used aspacer from a block of acrylic sheet Thekey here is to get the dish focal point at the15-turn point of the feed antenna whichis also at about the lip of the reflector cup

Fig 2358mdashWelded pipe fitting mountbracket for FABStar dish antenna

Fig 2357mdashRain cover for preamp usinga two-liter soft-drink bottle withaluminum foil tape for protection fromsun damage

The W1GHZ data for this focal point is5006 mm from the bottom edge of the dishand 7444 mm from the top edge A two-string measurement of this point can con-firm the focal point all as shown by Wadein his writings When mounting this feedantenna the constructor must be cautiousto aim the feed at the beam-center of thedish and not the geometric center as theoriginal microwave horn antenna wereconstructed Taking the illumination angleinformation noted above the helix feedantenna should be aimed 55deg down fromthe geometric center of the dish

As illustrated in Fig 2356 a DEMpreamp was directly mounted to the feedhelix using TNC connector that had beenchosen for this case as an N connector isquite large for the S-band helix A malechassis mount connector should bemounted on either the preamp or theantenna so that the preamp can be directlyconnected to the antenna without anyadaptors This photo also illustrates howthe reflector cup walls were riveted to thereflector plate Exposed connectors must

be protected from rainwater Commonlymaterials such as messy Vinyl Mastic Pads(3M 2200) or Hand Moldable Plastic(Coax Seal) are used Since this is a tightlocation for such mastic applications arain cover was made instead from a two-liter soft-drink bottle as shown in Fig2357 Properly cutting off the top of thebottle allows it to be slid over the helixreflector cup and secured with a large hoseclamp Sun-damage protection of the plas-tic bottle must be provided and that wasdone with a wrapping of aluminum foilpressure-sensitive-adhesive tape

There are many methods for mountingthis dish antenna to your elevation boomConstructors must give consideration tothe placement of the dish to reduce thewind loading and off-balance to the rota-tor system by this mounting In the illus-trated installation the off-balance issuewas not a major factor but the dish wasplaced near the center of the elevationboom between the pillow block bearingsupports As there is already sizeable alu-minum plate for these bearings the dishwas located to ldquocoverrdquo part of that plateso as to not add measurably to the existingwind-loading area of the overall assem-bly A mounting bracket provided with thestock dish clamps to the end of a standard2-inch pipe (actual measure φ238 inch)stanchion This bracket was turned aroundon the dish and clamped to the leg of awelded pipe Tee assembly see Fig 2358Pipe reducing fittings were machined andfitted in the Tee top bar which was cut inhalf for clamping over the 112-inch pipeused for the elevation boom Bolts wereinstalled through drilled hole and used toclamp this assembly


2326 Chapter 23

Fig 2360mdashA modified antenna baseplate assembly See the text for adescription

Fig 2359mdashThe antenna parts as received from Teksharp

AN INTEGRATED DUAL-BAND ANTENNA SYSTEMAn effective system can be built start-

ing with off-the-shelf componentsmdashtheTeksharp 12-meter dish and AIDC-3731AA downconverter These systemsinclude not only antennas but also highquality receiving converters both ofwhich are covered here

Operators are finding an increased availa-bility of components for their stations pro-viding them with a broad selection of theneeded equipment9 The products de-scribed here allow a single dish antenna toprovide for the required dual-band opera-tion with an S-band (23 GHz) downlinkand L-band (12 GHz) uplink

A new company has surfaced on theamateur equipment horizon TeksharpTeksharp is providing kits for both 12- and18-meter-diameter parabolic dish anten-nas Additionally S-band receiving con-verters are available from a numberof different suppliers including TeksharpHere Dick Jansson WD4FAB selected awell-proven converter the modified AIDC-3731AA from Bob Seydler K5GNA Bobtakes commercial converters and modifiesthem for S-band amateur service includingan upgrade of the front-end band-pass fil-tering This down-converter was selectedfor its superior and proven passband filter-ing allowing an L-band transmitting uplinkon the same antenna as the S-band down-link

The antenna system described here in-cludes the dish antenna its dual-band feedsystem and the receiving converter Thesethree elements are critical for high qualitycommunications This antenna system wascombined with a proven 40-W towermounted L-band amplifier also describedin this chapter resulting in a fully func-tioning station

THE TEKSHARP 12 METER DISHThe assembly methods are expected to

be the same for the 18-meter dish Thatlarger antenna provides additional perfor-mance and flexibility if desired The gainsfor the 12-meter dish are 210 dBi atL-band and 266 dBi at S-band

For this project the antenna arrived ina compact 36times12times4 inch box of partsFig 2359 shows these parts laid out forassembly A set of well machined andformed aluminum ribs is the key to anyparabolic dish design and these are wellexecuted WD4FAB measured the dimen-sions of these ribs to understand the basicdimensional features of the dish Thesefigures are 1204 mm 245 mm and 370 mmfor diameter depth and focus respec-tively Therefore the resulting focus todiameter ratio (FD) is 0307

the elevation boom In the installationshown in Fig 2360 at WD4FAB a modi-fied mounting from a previous dishdescribed elsewhere in this chapter wasused If your arrangement is more conven-tional you may be able to make use of theTeksharp mounting hardware withoutmodification

Before starting the assembly a copy ofa rib shape was made in order to developsome cardboard templates representingthe dish surface A 602-mm circularradius template was also fabricated to aidthe author in shaping the perimeter bandsto dimension rather than by guess Thedish-surface template was used to checkand maintain the parabolic shape of thedish surface as the mesh cloth petals wereassembled to the ribs These petals do notalways follow the rib shape in the spacebetween the ribs and the use of the tem-plate helped correct those surface inaccu-racies while still under construction TheAntennas chapter of this Handbook andthe ARRL Antenna Book10 provide excel-lent information on dish antenna construc-tion methods

Following the well-written Teksharpinstructions the ribs were assembled tothe circular hub plate and the structure thenclosed with the formed perimeter bandsIn the authorrsquos shop he fashioned the abil-ity to hold the framework in a shop visemaking the assembly task much easier Onone of the rib ends at the top of the dish anut was replaced with a riveted-in-placeblind anchor nut to allow the coax cablesto be clamped to the dish rim without hav-ing to simultaneously handle too muchloose hardware while performing that step

It is now time to create a parabolic dish

Separate plastic packages include theantenna assembly screws and the antennamounting bolts Teksharp also sent somewell illustrated assembly instructions anda plastic template for the petals (or gores)for the hardware cloth covering the dish

The included hex-head screws and nutsfor the antenna assembly were high qual-ity stainless steel The U bolts and mast-mounting clamp hardware provided werealso high quality but the bolts and clampswere conventionally plated It is useful tonote that parts fabricated and finished inthese materials can quickly corrode andbecome unusable in a humid climate Themachined parts for these antennas werevery well made and finished and theywere a pleasure to work with

Teksharp provides a well-suited bracketplate that supports the feed boom while alsoproviding for the mounting of the dish to



Fig 2361mdashDish antenna during assembly

out of this strong and lightweight frame-work The constructor must provide hisown fabric cloth for this part of the assem-bly The kit recommendations are to usefrac14-inch galvanized cloth a low cost itemavailable at most hardware stores Theauthor had some eight-wires-per-inch alu-minum cloth left over from a previous at-tempt to build a dish antenna This wasideal as galvanized material has a habit ofeventually rusting away in a humid cli-mate Fig 2361 shows the partially as-sembled dish in the authorrsquos shop

ANTENNA FEEDEarly dish antennas for these ranges

used helical antennas as feeds The experi-ences of other operators in the testing ofAO-40 antennas has shown that low FDparabolic antennas such as this one aremost effectively fed using patch rather thanhelical antennas (See the several articlesby Jerry Brown K5OE at membersaolcomk5oe Also see articles by RobertSuding WOslashLMD at wwwultimatechargercomdishhtml)

WOslashLMD provides some useful multi-band patch antennas that can be purchasedfor this service as does Teksharp Theauthor decided to follow K5OErsquos guidanceas recently published (see Fig 2362)11

The sharp-eyed reader may observe thatWD4FAB made some modifications to theoriginal patch design through the addi-tion of some nylon screws on the L-bandpatch Please be advised to build this an-tenna exactly as in the original article un-less you have some quality laboratory testequipment Fortunately WD4FAB hadthe use of a good network analyzer at theAMSAT Laboratory

Fig 2362mdashDetailsof the dual-bandpatch-feed system

AIDC-3731AA S BANDDOWNCONVERTER

The next element of this system is theAIDC-3731AA downconverter fromK5GNA This converter offers one ofthe lower-cost approaches to receiving AO-40rsquos 2401 MHz downlink signal Fig 2363shows the converter mounted directly tothe male Type N connector on the S-bandpatch antenna The output port provides a2-meter IF output through the F connectoron the side

This converter is now available with alow overhead internal voltage regulatorallowing it to be powered by a 138 V dcsupply source and still obtain proper regu-lation of the 12 V dc needed for the inter-nal circuits There is a considerableadvantage in using this regulation schemeas it keeps the total power dissipation lowthus holding down the temperature risefrom the 25 W of power dissipation Thereis interest in keeping this power dissipa-tion low to minimize frequency shift dueto temperature rise Converters exposed tothe sun will have noticeable frequencyshifts with clouds shading the sun This138 V dc power is supplied to the con-verter through a bias T in the shack andRG-6 coaxial cable to the IF connector ofthe converter

FEED ASSEMBLYFollowing the directions in K5OErsquos

article for the dual-band patch antennaWD4FAB provided a mounting angle onthe patch assembly using a piece of steelstrapping angle The author also machinedan aluminum sleeve adapter for mountingbetween the J-shaped feed boom and thissteel angle as can be seen in Fig 2363

Fig 2363mdashThis photoshows the downconverterassembled to the rear ofthe feed assembly


2328 Chapter 23

Glossary of Satellite TerminologyAMSATmdashA registered trademark of the Radio AmateurSatellite Corporation a nonprofit scientificeducationalorganization located in Washington DC It builds andoperates Amateur Radio satellites and has sponsored theOSCAR program since the launch of OSCAR 5 (AMSATPO Box 27 Washington DC 20044)

Anomalistic periodmdashThe elapsed time between twosuccessive perigees of a satellite

AO-mdashThe designator used for AMSAT OSCAR spacecraftin flight by sequence number

AOSmdashAcquisition of signal The time at which radio signalsare first heard from a satellite usually just after it risesabove the horizon

ApogeemdashThe point in a satellitersquos orbit where it is farthestfrom Earth

Area coordinatorsmdashAn AMSAT corps of volunteers whoorganize and coordinate amateur satellite user activity intheir particular state municipality region or country Thisis the AMSAT grassroots organization set up to assist allcurrent and prospective OSCAR users

Argument of perigeemdashThe polar angle that locates theperigee point of a satellite in the orbital plane drawnbetween the ascending node geocenter and perigee andmeasured from the ascending node in the direction ofsatellite motion

Ascending nodemdashThe point on the ground track of thesatellite orbit where the sub-satellite point (SSP) crossesthe equator from the Southern Hemisphere into theNorthern Hemisphere

Az-el mountmdashAn antenna mount that allows antennapositioning in both the azimuth and elevation planes

AzimuthmdashDirection (side-to-side in the horizontal plane)from a given point on Earth usually expressed in degreesNorth = 0deg or 360deg East = 90deg South = 180deg West = 270deg

Circular polarization (CP) mdash A special case radio energyemission where the electric and magnetic field vectorsrotate about the central axis of radiation As viewed alongthe radiation path the rotation directions are considered tobe right-hand (RHCP) if the rotation is clockwise and left-hand (LHCP) if the rotation is counterclockwise

Descending node mdash The point on the ground track of thesatellite orbit where the sub-satellite point (SSP) crossesthe equator from the Northern Hemisphere into theSouthern Hemisphere

Desense mdash A problem characteristic of many radioreceivers in which a strong RF signal overloads thereceiver reducing sensitivity

Doppler effect mdash An apparent shift in frequency caused bysatellite movement toward or away from your location

Downlink mdash The frequency on which radio signals origi-nate from a satellite for reception by stations on Earth

Earth station mdash A radio station on or near the surface ofthe Earth designed to transmit or receive tofrom aspacecraft

Eccentricity mdash The orbital parameter used to describe the

geometric shape of an elliptical orbit eccentricity valuesvary from e = 0 to e = 1 where e = 0 describes a circleand e = 1 describes a straight line

EIRP mdash Effective isotropic radiated power Same as ERPexcept the antenna reference is an isotropic radiator

Elliptical orbit mdash Those orbits in which the satellite pathdescribes an ellipse with the Earth at one focus

Elevation mdash Angle above the local horizontal planeusually specified in degrees (0deg = plane of the Earthrsquossurface at your location 90deg = straight up perpendicularto the plane of the Earth)

Epoch mdash The reference time at which a particular set ofparameters describing satellite motion (Keplerianelements) are defined

EQX mdash The reference equator crossing of the ascendingnode of a satellite orbit usually specified in UTC anddegrees of longitude of the crossing

ERP mdash Effective radiated power System power outputafter transmission-line losses and antenna gain (refer-enced to a dipole) are considered

ESA mdash European Space Agency A consortium ofEuropean governmental groups pooling resources forspace exploration and development

FO- mdash The designator used for Japanese amateursatellites by sequence number Fuji-OSCAR 12 and Fuji-OSCAR 20 were the first two such spacecraft

Geocenter mdash The center of the EarthGeostationary orbit mdash A satellite orbit at such an altitude

(approximately 22300 miles) over the equator that thesatellite appears to be fixed above a given point

Groundtrack mdash The imaginary line traced on the surfaceof the Earth by the subsatellite point (SSP)

Inclination mdash The angle between the orbital plane of asatellite and the equatorial plane of the Earth

Increment mdash The change in longitude of ascending nodebetween two successive passes of a specified satellitemeasured in degrees West per orbit

Iskra mdash Soviet low-orbit satellites launched manually bycosmonauts aboard Salyut missions Iskra means ldquosparkrdquoin Russian

JAMSAT mdash Japan AMSAT organizationKeplerian Elements mdash The classical set of six orbital

element numbers used to define and compute satelliteorbital motions The set is comprised of inclination RightAscension of Ascending Node (RAAN) eccentricityargument of perigee mean anomaly and mean motionall specified at a particular epoch or reference year dayand time Additionally a decay rate or drag factor isusually included to refine the computation

LEO mdash Low Earth Orbit satellite such as the Phase 1 andPhase 2 OSCARs

LHCP mdash Left-hand circular polarizationLOS mdash Loss of signal mdash The time when a satellite

passes out of range and signals from it can no longer

This angle also provided an added supportfor the AIDC-3731AA converter shownstrapped down with a plastic cable tie Asassembled this is a robust feed assembly

Mounting of the patch assembly wasdone with the patches aligned parallel tothe plane of the dish and on the dish centerline Place the S-band reflector at the focal

distance 370 mm (1457 inches) from thedish surface at the center This adjustmentis made by moving the feed boom along itsmounting clamps until the proper mea-surement is achieved That is all you haveto do You can play with mirrors as in theinstructions to focus the sun on thepatches but doing this adjustment by mea-

surement is easier and it is all that reallyneeds to be done

K5OE cautions that rain bird droppingsand bugs can mess up the tuning andoperation of the patch feed antennas Headvises the use of some kind of protectionfor antennas In addition the author has anaversion to having water in hard-to-reach



Project OSCAR mdash The California-based group amongthe first to recognize the potential of space for AmateurRadio responsible for OSCARs I through IV

QRP days mdash Special orbits set aside for very low poweruplink operating through the satellites

RAAN mdash Right Ascension of Ascending Node TheKeplerian element specifying the angular distancemeasured eastward along the celestial equator betweenthe vernal equinox and the hour circle of the ascendingnode of a spacecraft This can be simplified to meanroughly the longitude of the ascending node

Radio Sputnik mdash Russian Amateur Radio satellites (seeRS )

Reference orbit mdash The orbit of Phase II satellites begin-ning with the first ascending node during that UTC day

RHCP mdash Right-hand circular polarizationRS mdash The designator used for most Russian Amateur

Radio satellites (RS-1 through RS-15 for example)Satellite pass mdash Segment of orbit during which the

satellite ldquopassesrdquo nearby and in range of a particularground station

Sidereal day mdash The amount of time required for the Earthto rotate exactly 360deg about its axis with respect to theldquofixedrdquo stars The sidereal day contains 143607 minutes(see Solar day)

Solar day mdash The solar day by definition contains exactly24 hours (1440 minutes) During the solar day the Earthrotates slightly more than 360deg about its axis with respectto ldquofixedrdquo stars (see Sidereal day)

Spin modulation mdash Periodic amplitude fade-and-peakresulting from the rotation of a satellitersquos antennas aboutits spin axis rotating the antenna peaks and nulls

SSP mdash Subsatellite point Point on the surface of the Earthdirectly between the satellite and the geocenter

Telemetry mdash Radio signals originating at a satellite thatconvey information on the performance or status ofonboard subsystems Also refers to the information itself

Transponder mdash A device onboard a satellite that receivesradio signals in one segment of the spectrum amplifiesthem translates (shifts) their frequency to anothersegment of the spectrum and retransmits them Alsocalled linear translator

UoSAT-OSCAR (UO ) mdash Amateur Radio satellites builtunder the coordination of radio amateurs and educatorsat the University of Surrey England

Uplink mdash The frequency at which signals are transmittedfrom ground stations to a satellite

Visibility Circle mdash The range of area on the Earth that areldquoseenrdquo by a satellite This is also called the ldquofootprintrdquo forthat satellite

Window mdash Overlap region between acquisition circles oftwo ground stations referenced to a specific satelliteCommunication between two stations is possible whenthe subsatellite point is within the window

be heard This usually occurs just after the satellitegoes below the horizon

Mean anomaly (MA) mdash An angle that increases uniformlywith time starting at perigee used to indicate where asatellite is located along its orbit MA is usually specifiedat the reference epoch time where the Keplerian ele-ments are defined For AO-10 the orbital time is dividedinto 256 parts rather than degrees of a circle and MA(sometimes called phase) is specified from 0 to 255Perigee is therefore at MA = 0 with apogee at MA = 128

Mean motion mdash The Keplerian element to indicate thecomplete number of orbits a satellite makes in a day

Microsat mdash Collective name given to a series of smallamateur satellites having store-and-forward capability(OSCARs 14-19 for example)

Molniya mdash Type of elliptical orbit first used in the RussianMolniya series that features a ground track that more orless repeats on a daily basis

NASA mdash National Aeronautics and Space Administrationthe US space agency

Nodal period mdash The amount of time between two succes-sive ascending nodes of satellite orbit

Orbital elements mdash See Keplerian ElementsOrbital plane mdash An imaginary plane extending through-

out space that contains the satellite orbitOSCAR mdash Orbiting Satellite Carrying Amateur RadioPACSATmdash Packet radio satellite (see Microsat and

UoSAT-OSCAR)Pass mdash An orbit of a satellitePassband mdash The range of frequencies handled by a

satellite translator or transponderPerigee mdash The point in a satellitersquos orbit where it is closest

to EarthPeriod mdash The time required for a satellite to make one

complete revolution about the Earth See Anomalisticperiod and Nodal period

Phase I mdash The term given to the earliest short-lived lowEarth orbit (LEO) OSCAR satellites that were notequipped with solar cells When their batteries weredepleted they ceased operating

Phase 2 mdash LEO OSCAR satellites Equipped with solarpanels that powered the spacecraft systems and re-charged their batteries these satellites have been shownto be capable of lasting up to five years (OSCARs 6 7and 8 for example)

Phase 3 mdash Extended-range high-elliptical-orbit OSCARsatellites with very long-lived solar power systems(OSCARs 10 and 40 for example)

Phase 4 mdash Proposed OSCAR satellites in geostationaryorbits

Polar Orbit mdash A low circular orbit inclined so that itpasses over the Earthrsquos poles

Precession mdash An effect that is characteristic of AO-10and AO-40 orbits The satellite apogee SSP will graduallychange over time

coaxial connectors Water in these connec-tors does not ensure a good satellite signalTo solve both of these problems WD4FABwent shopping for an antenna cover at hisfavorite ldquoantenna parts storerdquo K-Mart Hefound help from Martha Stewart no less inthe form of a nice clear styrene plastic ldquo33quart airtight canisterrdquo

One of these canisters was modified tofit over the patch assembly and the feedboom This canister was also shortened toallow it to fit into the cover lip of anunmodified canister mounted on the ldquorearrdquoof the feed The modified canister wasmounted to the patch reflector with threesmall angle brackets as seen in Fig 2363

Some of the cutoff plastic cylinder shouldbe saved This can then be glued to the endof the cutoff container to shim that OD tofit into the inside diameter of the cover lipof the rear canister The author also epoxy-bonded a set of blind nuts to the inside ofthe canister so that the screws through thecover lip of the rear-mounted canister will


2330 Chapter 23

Fig 2364mdashThe33-quart plasticcanisterconverted for useas a radome atthe feedpoint

keep it together That arrangement is shownin Fig 2364 The slot in the front canisterthat passes the feed boom has space for thecoaxial cables for L and S band A furtherprotection measure was to cover the ex-posed plastic with aluminum foil tape asseen in Fig 2364 This was not done to areain front of the patch antennas This tape isthere to protect the plastic from sun dam-age although this type of clear plastic hasa good record in avoiding UV harm

INSTALLATIONWith all preparations made comple-

tion of the installation of the dish antennaand converter was a breeze Fig 2365shows the dish assembly bolted to theauthorrsquos old PrimeStar antenna mountJust remember to use the built-in screwadjustment provided in the PrimeStarmount to aim the dish centerline alongthe centerline of your antenna pointingsystem The beamwidths of L- and S-bandoperations in this assembly are fairly nar-row so your pointing precision will needto be pretty good Many of the details ofthe WD4FAB elevation boom system areshown in Fig 2365 as well

Before finally closing the protectiveplastic containers over the feed antennasbe sure that all of the coaxial cable con-nections are tight and the cables aredressed properly This final closure willneed to be done at this step in the assem-bly Be sure to arrange the coaxial cablesso that they donrsquot drag on the feed boomThe cable clamps at the top of the dish arethere to dress the cables and support thefeed boom This is shown in Fig 2366

Fig 2366 also shows the dish system inoperating position along with theU-band (70 cm) cross-polarized (CP)Yagi antenna on the far left and thetwo smaller M2 23CM22EZA antennas

that were tested previously The authorhas kept these two L-band antennasin service for use on 1296 MHz He placeda ground-commanded relay to switch be-tween the two antenna systems in the am-plifier box on the top of the tower This isalso convenient to use to compare the twoL-band antenna systems

ON THE AIRThis configuration was tested with the

AO-40 satellite (which is no longer opera-tional at the time of this writing) Testsshowed that AO-40 downlink signals on Sband 2401 MHz were really solid withthis system The pointing requirementswere narrow and had to be good to within3deg to 4deg based on the specified beam widthat these frequencies The noise floor ofAO-40 was clearly detectable about 2 dBabove cold sky noise

For the uplink WD4FAB had a usablereturn signal with 40 W of RF on L bandwhen the satellite ldquosquintrdquo was 20deg orlower as reported in note 10 When thesquint is low good downlink signals wererealized with only about 5-10 W PEP of L-band power When the author comparedthe Teksharp antenna on L band to the M223CM22EZA stacked antennas as shownin Fig 2366 he saw better than an S-unit(gt3-4 dB on his Kenwood TS-2000 trans-ceiver) improvement in downlink signalThis improved performance was seen inthe wider ranges of squint angles that canbe used with the Teksharp antenna on theL-band uplink When the AO-40 squintangles were greater than 20deg he still hadto use his U-band uplink transmitter withthe CP Yagi antenna

Measurements of Sun noise have beenattempted with this antenna system Thesehave been disappointing with values ofaround 2 dB seen This is compared to the

solid 5 dB of Sun noise measured with theWD4FAB previous PrimeStar dish Oneof the probable reasons for the loweredperformance can be attributed to the front-end band-pass filtering provided in thereceive converter The operating experi-ence with this system has been absolutelysolid however

IN SUMMARYIt is important to consider all of the

interrelated characteristics of an antennasystem It is insufficient to just whip upldquoanyrdquo antenna marry ldquoanyrdquo receive con-verter to that antenna and then use ldquoanyrdquotransmitting scheme to operate with full-duplex signals from high-performancesatellites Wersquove had the ability to em-ploy computer analysis as shown to us byGene Marcus W3PM with his spread-sheet analysis wwwamsatorgamsatftpsoftwarespreadsheetw3pm-ao40-v21zip

Manufacturers Antenna Teksharp(Rick Fletcher KG6IAL) wwwteksharpcom 5770 McKellar Dr SanJose CA 95129 inquiriesteksharpcom Price 12 meter dish $165 feedboom $40 dual-band (SL) patch feed$200 Downconverter Bob Seydler K5GNAmembersaolcomk5gnamyhomepage8522 Rebawood Humble TX 77346-1789 281-852-0252 bobk5gnacomPrice $100 setup for 12 V operation add$20

JUST THE BEGINNINGThis section barely nicks the surface of

satellite operating There is much more tolearn and enjoy It is suggested that youspend some time at the AMSAT Web siteYoursquoll pick up a wealth of informationthere Speaking of ldquopicking uprdquo grab acopy of the ARRL Radio Amateurrsquos Satel-lite Handbook and the ARRL Antenna Book(see your favorite dealer or buy it onARRLWeb) Between these two resourcesyoursquoll be able to tap just about all the ama-teur satellite knowledge yoursquore likely toneed

In the meantime see you in orbit

NOTES1QST December 1998 ldquoAn Inexpensive Az-

El Rotator Systemrdquo Jim Koehler VE5FP2McCaa William D ldquoHints on Using the

AMSAT-OSCAR 13 Mode S TransponderrdquoThe AMSAT Journal Vol 13 no 1 Mar1990 pp 21-22

3Miller James ldquoMode S mdash TomorrowrsquosDownlinkrdquo The AMSAT Journal Vol 15no 4 SepOct 1992 pp 14-15

4Krome Ed ldquoS band Reception Building theDEM Converter and Preamp Kitsrdquo TheAMSAT Journal Vol 16 no 2 MarApr1993 pp 4-6



Fig 2365mdashMounting details of the antenna system

Fig 2366mdashThe completed and tower-mounted antennasystem ready to go The 40-W 23-cm amplifier isenclosed in the box below the dish antenna

5Krome Ed ldquoDevelopment of a PortableMode S Ground Stationrdquo The AMSAT Jour-nal Vol 16 no 6 NovDec 1993 pp 25-28

6Krome Ed ldquoMode S Plug and Playrdquo TheAMSAT Journal Vol 14 no 1 Jan 1991pp 21-23 25

7Miller James ldquoA 60-cm S-Band DishAntennardquo The AMSAT Journal Vol 16 no2 MarApr 1993 pp 7-9

8Miller James ldquoSmall is Bestrdquo The AMSATJournal Vol 16 no 4 JulAug 1993 p 12

9R Jansson WD4FAB ldquoProduct Review-M2

23CM22EZA 12 GHz Antennardquo QST Sep2002 pp 59-61

10The ARRL Antenna Book 20th EditionChapter 19 Available from your localdealer or The ARRL Bookstore ARRL or-der no 9043 Telephone toll-free in theUS 888-277-5289 or 860-594-0355fax 860-594-0303 wwwarrlorgshoppubsalesarrlorg

11G Brown K5OE ldquoBuild This No-TuneDual-Band Feed for Mode LSrdquo TheAMSAT Journal Vol 26 no1 JanFeb2003 pp 12-16

SELECTED SATELLITEREFERENCESEquipment SelectionD DeMaw ldquoTrio-Kenwood TS-700S

2-Meter Transceiverrdquo QST Feb 1978pp 31-32

C Hutchinson ldquoTen-Tec 2510 Mode B Sat-ellite Stationrdquo QST Oct 1985 pp 41-43

D Ingram ldquoThe Ten-Tec 2510 OSCARSatellite StationConverterrdquo CQ Maga-zine Feb 1985 pp 44-46

J Kleinman ldquoICOM IC-290H All-Mode2-Meter Transceiverrdquo QST May 1983pp 36-37

J Lindholm ldquoICOM IC-471A 70-cmTransceiverrdquo QST Aug 1985 pp 38-39

R Schetgen Ed The ARRL Radio BuyerrsquosSourcebook and The ARRL RadioBuyerrsquos Sourcebook Vol 2 (NewingtonARRL 1991 and 1993) A compilationof Product Reviews from QST

R Roznoy Ed The ARRL VHFUHFRadio Buyerrsquos Sourcebook (NewingtonARRL 1997) A compilation of VHFand UHF Product Reviews from QST

M Wilson ldquoICOM IC-271A 2-Meter Mul-timode Transceiverrdquo QST May 1985 pp40-41

M Wilson ldquoYaesu Electronics CorpFT-726R VHFUHF Transceiverrdquo QSTMay 1984 pp 40-42

M Wilson ldquoYaesu FT-480R 2-Meter Mul-timode Transceiverrdquo QST Oct 1981 pp46-47

H Winard and R Soderman ldquoA Survey ofOSCAR Station Equipmentrdquo Orbit no16 Nov-Dec 1983 pp 13-16 and no 18Mar-Apr 1984 pp 12-16

S Ford ldquoPacComm PSK-1T Satellite Mo-

dem and TNCrdquo QST Jul 1993 p 46R Healy ldquoDown East Microwave 432PA

432-MHz Amplifier Kitrdquo QST Mar1993 p 66

R Healy ldquoDown East MicrowaveDEM432 No-Tune 432-MHz Trans-verterrdquo QST Mar 1993 p 64

R Jansson ldquoSSB Electronic SP-70 Mast-Mount Preamplifierrdquo QST Mar 1993p 63

S Ford ldquoQST Compares SSB ElectronicUEK-2000S and Down East MicrowaveSHF-2400 24-GHz Satellite Down-con-vertersrdquo QST Feb 1994 p 69

S Ford ldquoICOM IC-821H VHFUHF Mul-timode Transceiverrdquo QST Mar 1997pp 70-73

S Ford ldquoYaesu FT-847 HFVHFUHFTransceiverrdquo QST Aug 1998 pp 64-69

AntennasM Davidoff ldquoOff-Axis Circular Polariza-

tion of Two Orthogonal Linearly Polar-ized Antennasrdquo Orbit no 15 Sep-Oct1983 pp 14-15

JL DuBois ldquoA Simple Dish for Mode-LrdquoOrbit no 13 Mar-Apr 1983 pp 4-6

B Glassmeyer ldquoCircular Polarization andOSCAR Communicationsrdquo QST May1980 pp 11-15

RD Straw Ed The ARRL Antenna Book


2332 Chapter 23

(Newington ARRL 2003) Availablefrom your local radio store or fromARRL

R Jansson ldquoHelical Antenna Constructionfor 146 MHzrdquo Orbit May-Jun 1981 pp12-15

R JanssonrdquoKLM 2M-22C and KLM435-40CX Yagi Antennasrdquo QST Oct1985 pp 43-44

R Jansson ldquo70-Cm Satellite AntennaTechniquesrdquo Orbit no 1 Mar 1980pp 24-26

R Messano ldquoAn Indoor Loop for Satel-lite Workrdquo QST Jul 1999 p 55

C Richards ldquoThe Chopstick HelicalrdquoOrbit no 5 Jan-Feb 1981 pp 8-9

V Riportella ldquoAmateur Satellite Commu-nicationsrdquo QST May 1985 pp 70-71

G Schrick ldquoAntenna Polarizationrdquo TheARRL Antenna Compendium Vol 1(Newington ARRL 1985) pp 152-156

A Zoller ldquoTilt Rather Than Twistrdquo Or-bit no 15 Sep-Oct 1983 pp 7-8

R Jansson ldquoM2 Enterprises 2M-CP22and 436-CP30 Satellite Yagi Anten-nasrdquo QST Nov 1992 p 69

S Ford ldquoM2 Enterprises EB-144 Egg-beater Antennardquo QST Sep 1993 p 75

MicrosatsMills SE ldquoStep Up to the 38400 Bps

Digital Satellitesrdquo QST Apr 2000 pp42-45

Loughmiller D and B McGwierldquoMicrosat The Next Generation ofOSCAR Satellitesrdquo Part 1 QST May1989 pp 37-40 Part 2 QST Jun 1989pp 53-54 70

Loughmiller D ldquoSuccessful OSCARLaunch Ushers in the rsquo90srdquo QST May

1990 pp 40-41Loughmiller D ldquoWEBERSAT-OSCAR

18 Amateur Radiorsquos Newest Eye in theSkyrdquo QST Jun 1990 pp 50-51

Ford S ldquoThe Road Less Traveledrdquo QSTApr 1996 p 58

Ford S ldquoKITSAT-OSCAR 23 ReachesOrbitrdquo QST Oct 1992 p 93

Ford S ldquoSatellite on a String SEDSAT-1rdquo QST Nov 1992 p 113

Ford S ldquoWEBERSATmdashStep by SteprdquoQST Dec 1992 p 63

Ford S ldquoAMRAD-OSCAR 27rdquo QST Dec1993 p 107

Ford S ldquoTwo More PACSATsrdquo QSTOct 1993 p 98

Soifer R ldquoAO-27 An FM Repeater in theSkyrdquo QST Jan 1998 pp 64-65

Ford S ldquoMeet the MultifacetedSUNSATrdquo QST Mar 1999 p 90

Ford S ldquoFlash Three New Satellites inOrbitrdquo QST Mar 2000 p 92

Soifer R ldquoUO-14 A User-Friendly FMRepeater in the Skyrdquo QST Aug 2000p 64

OSCAR 40Coggins B ldquoA Box for Phase 3Drdquo QST

Jun 1997 p 94Ford S and Z Lau ldquoGet Ready for Phase

3Drdquo Part 1 QST Jan 1997 p 28 Part2 QST Feb 1997 p 50 Part 3 QSTMar 1997 p 42 Part 4 QST Apr 1997p 45 Part 5 QST May 1997 p 28

Ford S ldquoPhase 3D The UltimateEasySatrdquo QST May 1995 p 21

Ford S ldquoPhase 3D Updaterdquo AmateurSatellite Communication QST Dec1994 p 105

Krome E ldquoGetting Started with AMSAT-

OSCAR 40rdquo QST July 2001 p 42Krome E Mode S The Book 2001 AO-

40P3D Update Complete guide to op-erating satellite S-band Available fromAMSAT-NA

Tynan B and R Jansson ldquoPhase 3DmdashASatellite for Allrdquo Part 1 QST May1993 p 49 Part 2 QST Jun 1993 p 49

ldquoPutting the Finishing Touches on Phase3Drdquo QST Oct 1988 p 20

Fuji-OSCARsFord S ldquoK1CErsquos Secret OSCAR-20 Sta-

tionrdquo QST Mar 1993 p 47Ford S ldquoFuji-OSCAR 20 Mode JArdquo

QST Sep 1993 p 104

SoftwareFord S ldquoShort TakesmdashNova for Win-

dows 32rdquo QST Apr 2000 p 65Ford S ldquoWill Orsquo the WiSPrdquo QST Feb

1995 p 90Ford S ldquoSatellite-Tracking Softwarerdquo

QST Dec 1993 p 89

General Texts and ArticlesM Davidoff The Radio Amateurrsquos Satellite

Handbook (Newington ARRL 2000)S Ford ldquoAn Amateur Satellite Primerrdquo

QST Apr 2000 p 36G McElroy ldquoKeeping Track of OSCAR

A Short Historyrdquo QST Nov 1999 p 65The ARRL Satellite Anthology

(Newington ARRL 1999)The ARRL Operating Manual (Newington

ARRL 2000)The AMSAT-Phase III Satellite Opera-

tions Manual prepared by Radio Ama-teur Satellite Corp and Project OSCARInc 1985 Available from AMSAT

Earth-Moon-Earth (EME)EME communication also known as

ldquomoonbouncerdquo has become a popularform of space communication The con-cept is simple The moon is used as apassive reflector for VHF and UHF sig-nals With a total path length of nearly500000 miles EME is the ultimate DXEME is a natural and passive propagationphenomenon and EME QSOs counttoward the WAS DXCC and VUCCawards EME opens up the VHF and UHFbands to a new universe of worldwideDX

The first demonstration of EME capa-bility was done by the US Army SignalCorps just after WW II In the 1950susing 400 MW of effective radiated powerthe US Navy established a moon relay linkbetween Washington DC and Hawaii that

could handle four multiplexed Teletype(RTTY) channels The first successfulamateur reception of EME signalsoccurred in 1953 by W4AO and W3GKP

It took until 1960 for two-way amateurcommunications to take place Using sur-plus parabolic dish antennas and high-power klystron amplifiers the EimacRadio Club W6HB and the Rhododen-dron Swamp VHF Society W1BUaccomplished this milestone in July 1960on 1296 MHz In the 1960s the first waveof amateur EME enthusiasts establishedamateur-to-amateur contacts on 144 MHzand 432 MHz In April 1964 W6DNGand OH1NL made the first 144-MHzEME QSO 432-MHz EME experimenta-tion was delayed by the 50-W power limit(removed January 2 1963) Only one

month after the first 144-MHz QSO wasmade the 1000-ft-diameter dish atArecibo Puerto Rico was used to dem-onstrate the viability of 432-MHz EMEwhen a contact was made betweenKP4BPZ and W1BU The first amateur-to-amateur 432-MHz EME QSO occurredin July 1964 between W1BU andKH6UK

The widespread availability of reliablelow-noise semiconductor devices alongwith significant improvements in Yagiarrays ushered in the second wave of ama-teur activity in the 1970s Contacts be-tween stations entirely built by amateursbecame the norm instead of the excep-tion In 1970 the first 220- and 2304-MHz EME QSOs were made followedby the first 50-MHz EME QSO in 1972



Fig 2368mdashVariations in EME path loss can be determined from this graph SDrefers to semi-diameter of the moon which is indicated for each day of the year inThe Nautical Almanac

Fig 2367mdashTommy Henderson WD5AGO pursues 144-MHz EME from his TulsaOklahoma QTH with this array Local electronics students helped withconstruction

1970s activity was still concentrated on144 and 432 MHz although 1296-MHzactivity grew

As the 1980s approached another quan-tum leap in receive performance occurredwith the use of GaAsFET preamplifiersThis and improvements in Yagi perfor-mance (led by DL6WUrsquos log-taper designwork) and the new US amateur poweroutput limit of 1500 W have put EME inthe grasp of most serious VHF andUHF operators The 1980s saw 144- and432-MHz WAS and WAC become a real-ity for a great number of operators The1980s also witnessed the first EME QSOson 3456 MHz and 5760 MHz (1987)

followed by EME QSOs on 902 MHz and10 GHz (1988)

EME is still primarily a CW mode Asstations have improved SSB is now morepopular Regardless of the transmissionmode successful EME operating requires

1) As close to the legal power output aspossible

2) A fairly large array (compared toOSCAR antennas)

3) Accurate azimuth and elevation rota-tion

4) Minimal transmission-line losses5) A low system noise figure prefer-

ably with the preamplifier mounted at thearray

CHOOSING AN EME BANDMaking EME QSOs is a natural progres-

sion for many weak-signal terrestrialoperators Looking at EME path loss vsfrequency (Fig 2368) it may seem as ifthe lowest frequency is best because ofreduced path loss This is not entirely trueThe path-loss graph does not account forthe effects of cosmic and man-made noisenor does it relate the effects of ionosphericscattering and absorption Both short- andlong-term fading effects also must be over-come

50-MHz EME is quite a challenge asthe required arrays are very large In addi-tion sky noise limits receiver sensitivityat this frequency Because of power andlicensing restrictions it is not likely thatmany foreign countries will be able to geton 50-MHz EME

144 MHz is probably the easiest EMEband to start on It supports the largestnumber of EME operators Commercialequipment is widely available a 144-MHzEME station can almost be completelyassembled from off-the-shelf equipment222 MHz is a good frequency for EMEbut there are only a handful of active sta-tions and 222 MHz is available only inITU Region 2

432 MHz is the most active EME bandafter 144 MHz Libration fading is more ofa problem than at 144 MHz but sky noiseis more than an order of magnitude lessthan on 144 MHz The improved receivesignal-to-noise ratio may more than makeup for the more rapid fading However432-MHz activity is most concentratedinto the one or two weekends a monthwhen conditions are expected to be best

902 MHz and above should be consid-ered if you primarily enjoy experimentingand building equipment If you plan tooperate at these frequencies an unob-structed moon window is a must Theantenna used is almost certain to be a dish902 MHz has the same problem that 222MHz has mdash itrsquos not an international bandEquipment and activity are expected to belimited for many years

1296 MHz currently has a good amountof activity from all over the world Recentequipment improvements indicate 1296MHz should experience a significantgrowth in activity over the next few years2300 MHz has received renewed interestIt suffers from nonaligned internationalband assignments and restrictions in dif-ferent parts of the world

ANTENNA REQUIREMENTSThe tremendous path loss incurred over

the EME circuit requires a high-powertransmitter a low-noise receiver and ahigh-performance antenna array Al-


2334 Chapter 23

though single-Yagi QSOs are possiblemost new EME operators will rapidlybecome frustrated unless they are able towork many different stations on a regularbasis Because of libration fading andthe nature of weak signals a 1- or 2-dBincrease in array gain will often be per-ceived as being much greater An im-portant antenna parameter in EMEcommunications is the antenna noisetemperature This refers to the amount ofnoise received by the array The noisecomes from cosmic noise (noise generatedby stars other than the sun) Earth noise(thermal noise radiated by the Earth) andnoise generated by man-made sourcessuch as power-line leaks and other broad-band RF sources

Yagi antennas are almost universallyused on 144 MHz Although dish antennasas small as 24 ft in diameter have beensuccessfully used they offer poor gain-tosize trade-offs at 144 MHz The minimumarray gain for reliable operation is about18 dBd (201 dBi) The minimum arraygain should also allow a station to hear itsown echoes on a regular basis This is pos-sible by using four 22-λ Yagis The 12-element 25-λ Yagi described in theAntennas chapter is an excellent choiceWhen considering a Yagi design youshould avoid old-technology Yagis thatis designs that use either constant-widthspacings constant-length directors or acombination of both These old-designYagis will have significantly poorer sidelobes a narrower gain bandwidth and asharper SWR bandwidth than modernlog-taper designs Modern wideband de-signs will behave much more predictablywhen stacked in arrays and unlike manyof the older designs will deliver close to3 dB of stacking gain

222-MHz requirements are similar tothose of 144 MHz Although dish antennasare somewhat more practical Yagis stillpredominate The 16-element 38-λ Yagidescribed in the Antennas chapter is a goodbuilding block for 222-MHz EME Four ofthese Yagis are adequate for a minimal 222-MHz EME station but six or eight will pro-vide a much more substantial signal

At 432 MHz parabolic-dish antennasbecome viable The minimum gainfor reliable 432-MHz EME operation is24 dBi

Yagis are also used on 432 MHz The22-element Yagi described in the Anten-nas chapter is an ideal 432-MHz designFour of the 22-element Yagis meet the24-dBi-gain criteria and have been usedsuccessfully on EME If you are going touse a fixed polarization Yagi array youshould plan on building an array with sub-stantially more than 24-dBi gain if you

desire reliable contacts with small sta-tions This extra gain is needed to over-come polarization misalignment

At 902 MHz and above the only an-tenna worthy of consideration is a para-bolic dish While it has been proven thatYagi antennas are capable of making EMEQSOs at 1296 MHz Yagi antennaswhether they use rod or loop elements aresimply not practical

EME QSOs have been made at 1296MHz with dishes as small as 6 ft in diam-eter For reliable EME operation withsimilarly equipped stations a 12-ft diam-eter dish (31 dBi gain at 1296 MHz) is apractical minimum TVRO dishes whichare designed to operate at 3 GHz makeexcellent antennas provided they have anaccurate surface area The one drawbackof TVRO dishes is that they usually havean undesirable Fd ratio More informa-tion on dish construction and feeds can befound in The ARRL Antenna Book and TheARRL UHFMicrowave ExperimenterrsquosManual

POLARIZATION EFFECTSAll of the close attention paid to operat-

ing at the best time such as nighttime peri-gee with high moon declination and lowsky temperatures is of little use if signalsare not aligned in polarization between thetwo stations attempting to make contactThere are two basic polarization effectsThe first is called spatial polarizationSimply stated two stations (using az-elmounts and fixed linear polarization) thatare located far apart will usually not havetheir arrays aligned in polarization as seenby the moon Spatial polarization can eas-ily be predicted given the location of bothstations and the position of the moon

The second effect is Faraday rotationThis is an actual rotation of the radio wavesin space and is caused by the charge levelof the Earthrsquos ionosphere At 1296 MHzand above Faraday rotation is virtuallynonexistent At 432 MHz it is believedthat up to a 360deg rotation is common At144 MHz it is believed that the wavefrontcan actually rotate seven or more complete360deg revolutions When Faraday rotationis combined with spatial polarizationthere are four possible results

1) Both stations hear each other and canQSO

2) Station A hears station B station Bdoes not hear station A

3) Station B hears station A station Adoes not hear station B

4) Neither station A nor station B heareach other

At 144 MHz there are so many revolu-tions of the signal and the amount of Fara-day rotation changes so fast that

generally hour-long schedules are ar-ranged At 432 MHz Faraday rotation cantake hours to change Because of this half-hour schedules are used During the day-time you can count on 90 to 180deg ofrotation If both stations are operatingduring hours of darkness there will belittle Faraday rotation and the amount ofspatial polarization determines if a sched-ule should be attempted

At 1296 MHz and above circularpolarization is standard The predominantarray is a parabolic reflector which makescircular polarization easy to obtainAlthough the use of circular polarizationwould make one expect signals to be con-stant except for the effect of the moonrsquosdistance long-term fading of 6 to 9 dB isfrequently observed

With improved long-Yagi designs foryears the solution to overcoming polariza-tion misalignment has been to make thearray larger Making your stationrsquos sys-tem gain 5 or 6 dB greater than requiredfor minimal EME QSOs will allow you towork more stations simply by moving youfarther down the polarization loss curveAfter about 60deg of misalignment howevermaking your station large enough to over-come the added losses quickly becomes alifetime project See Fig 2369

At 432 MHz and lower Yagis arewidely used making the linear polariza-tion standard Although circular polariza-tion may seem like a simple solution topolarization problems when signals arereflected off the moon the polarizationsense of circularly polarized radio waveis reversed requiring two arrays of oppo-site polarization sense be used Initiallycrossed Yagis with switchable polari-zation may also look attractive Unfortu-nately 432-MHz Yagis are physicallysmall enough that the extra feed lines andswitching devices become complicatedand usually adversely affect array per-formance Keep in mind that even at 144 MHz Yagis cannot tolerate metalmounting masts and frames in line withthe Yagi elements

When starting out on EME keep in mindthat it is best to use a simple system Youwill still be able to work many of the largerfixed-polarization stations and those whohave polarization adjustment (only one sta-tion needs to have polarization control)Once you gain understanding and confi-dence in your simple array a more complexarray such as one with polarization rotationcan be attempted

RECEIVER REQUIREMENTSA low-noise receiving setup is essential

for successful EME work Many EME sig-nals are barely but not always out of the



noise To determine actual receiver per-formance any phasing line and feed linelosses along with the noise generated inthe receiver must be added to the arraynoise reception When all losses are con-sidered a system noise figure of05 dB (35 K) will deliver about all theperformance that can be used at 144 MHzeven when low-loss phasing lines and aquiet array are used

The sky noise at 432 MHz and above islow enough (cold sky is lt15 K (kelvins) at432 MHz and 5 K at 1296 MHz) so thelowest possible noise figure is desiredCurrent high-performance arrays will havearray temperatures near 30 K when un-wanted noise pickup is added in Phasingline losses must also be included alongwith any relay losses Even at 432 MHzit is impossible to make receiver noise in-significant without the use of a liquid-cooled preamplifier Current technologygives a minimum obtainable GaAsFETpreamplifier noise figure at room temper-ature of about 035 dB (24 K)

GaAsFET preamps have also been stan-dard on 1296 MHz and above for severalyears Noise figures range from about04 dB at 1296 MHz (30 K) to about 2 dB(170 K at 10 GHz) HEMT devices arenow available to amateurs but are of littleuse below 902 MHz because of 1f noiseAt higher frequencies HEMT deviceshave already shown impressively lownoise figures Current HEMT devices arecapable of noise figures close to 12 dB at10 GHz (93 K) without liquid cooling

At 1296 MHz a new noise-limiting fac-tor appears The physical temperature ofthe moon is 210 K This means that justlike the Earth it is a black-body radiatorThe additional noise source is the reflec-

Fig 2369mdashThe graph shows howquickly loss because of polarizationmisalignment increases after 45deg Thecurve repeats through 360deg showing noloss at 0deg and maximum loss at 90deg and270deg

tion of sun noise off the moon Just as a fullmoon reflects sunlight to Earth the rest ofthe electromagnetic spectrum is also re-flected On 144 and 432 MHz thebeamwidth of a typical array is wideenough (15deg is typical for 144 MHz 7deg for432 MHz) that the moon which subtendsa 05deg area is small enough to be insignifi-cant in the arrayrsquos pattern At 1296 MHzbeamwidths approach 2deg and moon-noisefigures of up to 5 dB are typical at fullmoon Stations operating at 2300 MHz andabove have such narrow array patterns thatmany operators actually use moon noise toassure that their arrays are pointed at themoon

A new weak-signal operator is encour-aged to experiment with receivers and fil-ters A radio with passband tuning orIF-shift capability is desired These fea-tures are used to center the passband andthe pitch of the CW signal to the frequencyat which the operatorrsquos ears perform bestSome operators also use audio filteringAudio filtering is effective in eliminatinghigh-frequency noise generated in theradiorsquos audio or IF stages This noise canbe very fatiguing during extended weaksignal operation The switched-capacitoraudio filter has become popular with manyoperators

TRANSMITTER REQUIREMENTSAlthough the maximum legal power

Fig 2370mdashTwo systems for switching a preamplifier in and out of the receiveline At A a single length of cable is used for both the transmit and receive lineAt B is a slightly more sophisticated system that uses two separate transmissionlines At C a high-isolation relay is used for TR switching The energizedposition is normally used on receive

Table 234Transmitter Power Required forEME Success

Power at the array

50 MHz 1500 W 144 MHz 1000 W 222 MHz 750 W 432 MHz 500 W 902 MHz 200 W1296 MHz 200 W2300 MHz and above 100 W

(1500 W out) is desirable the actual powerrequired can be considerably less depend-ing on the frequency of operation and sizeof the array Given the minimum arraygain requirements previously discussedthe power levels recommended for reason-able success are shown in Table 234

The amplifier and power supply shouldbe constructed with adequate cooling andsafety margins to allow extended slow-speed CW operation without failure Thetransmitter must also be free from drift andchirp The CW note must be pure and prop-erly shaped Signals that drift and chirpare harder to copy They are especiallyannoying to operators who use narrow CWfilters A stable clean signal will improveyour EME success rate


2336 Chapter 23

CALCULATING EMECAPABILITIES

Once all station parameters are knownthe expected strength of the moon echoescan be calculated given the path loss for theband in use (see Fig 2372) The formula forthe received signal-to-noise ratio is

S N = Po ndash Lt + Gt ndash P1 + Gr ndash Pn (1)

wherePo = transmitter output power (dBW)Lt = transmitter feed-line loss (dB)Gt = transmitting antenna gain (dBi)Pl = total path loss (dB)Gr = receiving antenna gain (dBi)Pn = receiver noise power (dBW)

Receiver noise power Pn is determinedby the following

s10n KBTlog10P (2)

whereK = 138times10ndash23 (Boltzmannrsquos constant)B = bandwidth (Hz)Ts = receiving system noise tempera-

ture (K)

Receiving system noise temperatureTs can be found from

Ts = Ta + (Lr ndash 1) T1 + Lr Tr (3)

whereTa = antenna temperature (K)Lr = receiving feed-line loss (ratio)T1 = physical temperature of feed line

(normally 290 K)Tr = receiver noise temperature (K)

An example calculation for a typical432-MHz EME link is

Po = +30 dBW (1000 W)Lt = 10 dBGt = 264 dBi (8 times 61-λ 22-el Yagis)P1 = 262 dBGr = 235 dBi (15 ft parabolic)Ta = 60 KLr = 102 (01-dB preamp at antenna)T1 = 290 KTr = 354 K (NT = 05 dB)Ts = 1019 KPn = ndash1885 dBSN = + 54 dB

It is obvious that EME is no place for acompromise station Even relativelysophisticated equipment provides less-than-optimum results

Fig 2371 gives parabolic dish gain fora perfect dish The best Yagi antennas willnot exceed the gain curve shown in the

Antennas chapter If you are using mod-ern log-taper Yagis properly spacedfigure about 28 to 29 dB of stacking gainFor old-technology Yagis 25 dB may becloser to reality Any phasing line andpower divider losses must also be sub-tracted from the array gain

LOCATING THE MOONThe moon orbits the Earth once in

approximately 28 days a lunar monthBecause the plane of the moonrsquos orbit istilted from the Earthrsquos equatorial plane byapproximately 235deg the moon swings ina sine-wave pattern both north and southof the equator The angle of departure ofthe moonrsquos position at a given time fromthe equatorial plane is termed declination(abbreviated decl) Declination angles ofthe moon which are continually changing(a few degrees a day) indicate the latitudeon the Earthrsquos surface where the moon willbe at zenith For this presentation posi-tive declination angles are used when themoon is north of the equator and negativeangles when south

The longitude on the Earthrsquos surfacewhere the moon will be at zenith is relatedto the moonrsquos Greenwich Hour Angleabbreviated GHA or GHA ldquoHour anglerdquois defined as the angle in degrees to thewest of the meridian If the GHA of themoon were 0deg it would be directly overthe Greenwich meridian If the moonrsquosGHA were 15deg the moon would be directlyover the meridian designated as 15deg Wlongitude on a globe As one can readilyunderstand the GHA of the moon is con-tinually changing too because of both theorbital velocity of the moon and theEarthrsquos rotation inside the moonrsquos orbitThe moonrsquos GHA changes at the rate ofapproximately 347deg per day

GHA and declination are terms that maybe applied to any celestial body TheAstronomical Almanac (available from theSuperintendent of Documents US Gov-ernment Printing Office) and other publi-cations list the GHA and decl of the sunand moon (as well as for other celestialbodies that may be used for navigation)for every hour of the year This infor-mation may be used to point anantenna when the moon is not visibleAlmanac tables for the sun may be usefulfor calibrating remote-readout systems

Using the AlmanacThe Astronomical Almanac and other

almanacs show the GHA and declinationof the sun or moon at hourly intervals forevery day of the period covered by thebook Instructions are included in suchbooks for interpolating the positions of thesun or moon for any time on a given date

The orbital velocity of the moon is notconstant and therefore precise interpola-tions are not linear

Fortunately linear interpolations fromone hour to the next or even from one dayto the next will result in data that is en-tirely adequate for Amateur Radio pur-poses If linear interpolations are madefrom 0000 UTC on one day to 0000 UTCon the next worse-case conditions existwhen apogee or perigee occurs near mid-day on the next date in question Undersuch conditions the total angular error inthe position of the moon may be as muchas a sixth of a degree Because it takes afull year for the Earth to orbit the sun thesimilar error for determining the positionof the sun will be no more than a few hun-dredths of a degree

If a polar mount (a system having oneaxis parallel to the Earthrsquos axis) is usedinformation from the Almanac may beused directly to point the antenna arrayThe local hour angle (LHA) is simply theGHA plus or minus the observerrsquos longi-tude (plus if east longitude minus if west)The LHA is the angle west of the obser-verrsquos meridian at which the celestial bodyis located LHA and declination infor-mation may be translated to an EME win-dow by taking local obstructions and anyother constraints into account

Azimuth and ElevationAn antenna system that is positioned in

azimuth (compass direction) and elevation(angle above the horizon) is called anaz-el system For such a system someadditional work will be necessary to con-vert the almanac data into useful informa-tion The GHA and decl information maybe converted into azimuth and elevationangles with the mathematical equationsthat follow A calculator or computer thattreats trigonometric functions may beused CAUTION Most almanacs list datain degrees minutes and either decimalminutes or seconds Generally computerprograms have typically required thisinformation in degrees and decimal frac-tions so a conversion may be necessarybefore the almanac data is entered

Determining az-el data from equationsfollows a procedure similar to calculatinggreat-circle bearings and distances for twopoints on the Earthrsquos surface There is oneadditional factor however Visualize twoobservers on opposite sides of the Earthwho are pointing their antennas at themoon Imaginary lines representing theboresights of the two antennas will con-verge at the moon at an angle of approxi-mately 2deg Now assume both observersaim their antennas at some distant starThe boresight lines now may be consid-



ered to be parallel each observer havingraised his antenna in elevation byapproximately 1deg The reason for the nec-essary change in elevation is that theEarthrsquos diameter in comparison to its dis-tance from the moon is significant Thesame is not true for distant stars or forthe sun

Equations for az-el calculations are

LHAcosDcosLcosDsinLsinEsin (4)

EcosKEsin

Ftan (5)

LcosEcosLsinEsinDsin

Ccos (6)

whereE = elevation angle for the sunL = your latitude (negative if south)D = declination of the celestial bodyLHA = local hour angle = GHA plus or

minus your longitude (plus if eastlongitude minus if west longitude)

F = elevation angle for the moonK = 001657 a constant (see text that

follows)C = true azimuth from north if sin LHA

is negative if sin LHA is positivethen the azimuth = 360 ndash C

Assume our location is 50deg N latitude100deg W longitude Further assume that theGHA of the moon is 140deg and its declinationis 10deg To determine the az-el informationwe first find the LHA which is 140 minus100 or 40deg Then we solve equation 4

40cos10cos50cos10sin50sinEsin382Eand061795Esin

Solving equation 5 for F we proceed(The value for sin E has already been de-termined in equation 4)

382cos006175061795

Ftan

= 076489

From this F the moonrsquos elevationangle is 374deg

We continue by solving equation 6 forC (The value of sin E has already beendetermined)

50cos382cos50sin06179510sin

Ccos

C therefore equals 1264deg To determineif C is the actual azimuth we find the po-larity for sin LHA which is sin 40deg and

has a positive value The actual azimuththen is 360 ndash C = 2336deg

If az-el data is being determined for thesun omit equation 5 equation 5 takes intoaccount the nearness of the moon Thesolar elevation angle may be determinedfrom equation 4 alone In the aboveexample this angle is 382deg

The mathematical procedure is the samefor any location on the Earthrsquos surface Re-member to use negative values for southerlylatitudes If solving equation 4 or 5 yields anegative value for E or F this indicates thecelestial body below the horizon

These equations may also be used todetermine az-el data for man-made satel-lites but a different value for the constantK must be used K is defined as the ratioof the Earthrsquos radius to the distance fromthe Earthrsquos center to the satellite

The value for K as given above 001657is based on an average Earth-moon dis-tance of 239000 miles The actual Earth-moon distance varies from approximately225000 to 253000 mi When this changein distance is taken into account it yieldsa change in elevation angle of approxi-mately 01deg when the moon is near thehorizon For greater precision in determin-ing the correct elevation angle for themoon the moonrsquos distance from the Earthmay be taken as

D = ndash150745 times SD + 474332

whereD = moonrsquos distance in milesSD = moonrsquos semi-diameter from the

almanac

Fig 2371mdashParabolic-antenna gain vs size frequency and surface errors Allcurves assumed 60 aperture efficiency and 10-dB power taper Reference JRuze British IEEE

Computer ProgramsDigital modes are also used for EME

communications The WSJT software forWindows includes a mode known as JT44This software enables moonbounce con-tacts using sound-card-equipped PCssingle Yagi antennas and under 200 wattsof RFmdashan accomplishment that seemedvirtually impossible in previous years Itnow appears possible that this mode andother digital modes that may appear in thefuture will place EME communicationwithin reach of hams with both modestantenna space and budgets Complete de-tails and operating instructions can beviewed by downloading the WSJT UserGuide at pulsarprincetonedu~joeK1JTWSJT300PDF

As has been mentioned a computer maybe used in solving the equations for azi-muth and elevation For EME work it isconvenient to calculate az-el data at 30-minute intervals or so and to keep the re-sults of all calculations handy during theEME window Necessary antenna-positioncorrections can then be made periodically

RealTrak prints out antenna azimuthand elevation headings for nearly anycelestial object It can be used with theKansas City Tracker program described inthe satellite section to track celestialobjects automatically VHF PAK providesreal-time moon and celestial object posi-tion information Two other real-timetracking programs are EME Tracker andthe VK3UM EME Planner

Libration Fading of EME SignalsOne of the most troublesome aspects of


2338 Chapter 23

Fig 2372mdashChart recording of moon echoes received at W2NFA on July 26 1973 at 1630 UTC Antenna gain 44 dBitransmitting power 400 W and system temperature 400 K

receiving a moonbounce signal besidesthe enormous path loss and Faraday rota-tion fading is libration fading This sec-tion will deal with libration (pronouncedlie-brayshun) fading its cause and effectsand possible measures to minimize it

Libration fading of an EME signal ischaracterized in general as fluttery rapidirregular fading not unlike that observedin tropospheric scatter propagation Fad-ing can be very deep 20 dB or more andthe maximum fading will depend on theoperating frequency At 1296 MHz themaximum fading rate is about 10 Hz andscales directly with frequency

On a weak CW EME signal librationfading gives the impression of a randomlykeyed signal In fact on very slow CWtelegraphy the effect is as though the key-ing is being done at a much faster speedOn very weak signals only the peaks oflibration fading are heard in the form ofoccasional short bursts or ldquopingsrdquo

Fig 2372 shows samples of a typicalEME echo signal at 1296 MHz These re-cordings made at W2NFA show the wildfading characteristics with sufficient SNratio to record the deep fades Circularpolarization was used to eliminate Fara-day fading thus these recordings are oflibration fading only The recording band-width was limited to about 40 Hz to mini-mize the higher sideband-frequencycomponents of libration fading that existbut are much smaller in amplitude Forthose who would like a better statisticaldescription libration fading is Raleighdistributed In the recordings shown in Fig2372 the average signal-return levelcomputed from path loss and mean reflec-tion coefficient of the moon is at about the+15 dB SN level

It is clear that enhancement of echoesfar in excess of this average level is ob-

served This point should be kept clearlyin mind when attempting to obtain echoesor receive EME signals with marginalequipment The probability of hearing anoccasional peak is quite good since ran-dom enhancement as much as 10 dB ispossible Under these conditions how-ever the amount of useful information thatcan be copied will be near zero Enthusias-tic newcomers to EME communicationswill be stymied by this effect since theyknow they can hear the signal strongenough on peaks to copy but canrsquot makeany sense out of what they try to copy

What causes libration fading Very sim-ply multipath scattering of the radiowaves from the very large (2000-mile di-ameter) and rough moon surface combinedwith the relative motion between Earth andmoon called librations To understandthese effects assume first that the Earthand moon are stationary (no libration) andthat a plane wave front arrives at the moonfrom your Earthbound station as shown inFig 2373A

The reflected wave shown n Fig 2373Bconsists of many scattered contributionsfrom the rough moon surface It is perhapseasier to visualize the process as if thescattering were from many small indi-vidual flat mirrors on the moon thatreflect small portions (amplitudes) of theincident wave energy in different direc-tions (paths) and with different pathlengths (phase) Those paths directedtoward the moon arrive at your antenna asa collection of small wave fronts (fieldvectors) of various amplitudes and phasesThe vector summation of all these coher-ent (same frequency) returned waves (andthere is a near-infinite array of them) takesplace at the feed point of your antenna (thecollecting point in your antenna system)The level of the final summation as mea-

sured by a receiver can of course haveany value from zero to some maximumRemember that we assumed the Earth andmoon were stationary which means thatthe final summation of these multipathsignal returns from the moon will be onefixed value The condition of zero relativemotion between Earth and moon is a rareevent that will be discussed later in thissection

Consider now that the Earth and moonare moving relative to each other (as theyare in nature) so the incident radio waveldquoseesrdquo a slightly different surface of themoon from moment to moment Sincethe lunar surface is very irregular thereflected wave will be equally irregularchanging in amplitude and phase frommoment to moment The resultant continu-ous summation of the varying multipathsignals at your antenna feed-point pro-duces the effect called libration fading ofthe moon-reflected signal

The term libration is used to describesmall perturbations in the movement ofcelestial bodies Each libration consistsmainly of its diurnal rotation moon libra-tion consists mainly of its 28-day rotationwhich appears as a very slight rockingmotion with respect to an observer onEarth This rocking motion can be visual-ized as follows Place a marker on the sur-face of the moon at the center of the moondisc which is the point closest to the ob-server as shown in Fig 2374 Over timewe will observe that this marker wandersaround within a small area This means thesurface of the moon as seen from the Earthis not quite fixed but changes slightly asdifferent areas of the periphery are ex-posed because of this rocking motionMoon libration is very slow (on the orderof 10-7 radians per second) and can bedetermined with some difficulty from pub-



Fig 2374mdash The moon appears toldquowanderrdquo in its orbit about the EarthThus a fixed marker on the moonrsquossurface will appear to move about in acircular area

Fig 2373mdash How the rough surface ofthe moon reflects a plane wave as onehaving many field vectors

lished moon ephemeris tablesAlthough the libration motions are very

small and slow the larger surface area ofthe moon has nearly an infinite number ofscattering points (small area) This meansthat even slight geometric movements canalter the total summation of the returnedmultipath echo by a significant amountSince the librations of the Earth and moonare calculable it is only logical to ask ifthere ever occurs a time when the totallibration is zero or near zero The answeris yes and it has been observed and veri-fied experimentally on radar echoes thatminimum fading rate (not depth of fade) iscoincident with minimum total librationCalculation of minimum total libration isat best tedious and can only be done suc-cessfully by means of a computer It is aproblem in extrapolation of rates of changein coordinate motion and in small differ-ences of large numbers

EME OPERATING TECHNIQUESMany EME signals are near the thresh-

old of readability a condition caused by acombination of path loss Faraday rotationand libration fading This weakness andunpredictability of the signals has led tothe development of techniques for theexchange of EME information that differfrom those used for normal terrestrialwork The fading of EME signals chopsdashes into pieces and renders strings ofdots incomplete This led to the use of theldquoT M O Rrdquo reporting system Differentbut similar systems are used on the lowbands (50 and 144 MHz) and the highbands (432 MHz and above) Tables 235and 236 summarize the differencesbetween the two systems

As equipment and techniques haveimproved the use of normal RST signalreports has become more common It isnow quite common for two stations work-ing for the first time to go straight to RSTreports if signals are strong enough Thesenormal reports let stations compare sig-nals from one night to the next EME QSOsare often made during the ARRL VHFcontests These contacts require theexchange of 4-digit grid locators On432 MHz and above the sending ofGGGG has come to mean ldquoPlease send meyour grid squarerdquo or conversely ldquoI amnow going to send my grid squarerdquo

The length of transmit and receive peri-ods is also different between the bands On50 and 144 MHz 2-minute sequences areused That is stations transmit for two fullminutes and then receive for two full min-utes One-hour schedules are used with theeastern-most station (referenced to the in-ternational date line) transmitting firstTable 237 gives the 2-minute sequence

Table 235Signal Reports Used on 144-MHzEME

T mdash Signal just detectableM mdash Portions of call copiedO mdash Complete call set has been receivedR mdash Both ldquoOrdquo report and call sets have

been receivedSK mdash End of contact


T mdash Portions of call copiedM mdash Complete calls copiedO mdash Good signalmdashsolid copy (possibly

enough for SSB work)R mdash Calls and reports copiedSK mdash End of contact

procedure On 222 MHz both the 144 and432-MHz systems are used

On 432 MHz and above 212-minutesequences are standard

The longer period is used to let stationswith variable polarization have adequatetime to peak the signal The last 30 sec-onds is reserved for signal reports onlyTable 238 provides more information onthe 432-MHz EME QSO sequence Thewestern-most station usually transmitsfirst However if one of the stations hasvariable polarization it may elect to trans-mit second to take the opportunity to usethe first sequence to peak the signal If bothstations have variable polarization thestation that transmits first should leave itspolarization fixed on transmit to avoidldquopolarization chasingrdquo

CW sending speed is usually in the 10 to13-wpm range It is often best to usegreater-than-normal spacing between in-dividual dits and dahs as well as betweencomplete letters This helps to overcomelibration fading effects The librationfading rate will be different from one bandto another This makes the optimumCW speed for one band different fromanother Keep in mind that characters senttoo slowly will be chopped up by typicalEME fading Morse code sent too fast willsimply be jumbled Pay attention to thesending practices of the more successfulstations and try to emulate them

Doppler shift must also be understoodAs the moon rises or sets it is movingtoward or away from objects on EarthThis leads to a frequency shift in the moonechoes The amount of Doppler shift isdirectly proportional to frequency At 144

MHz about 500 Hz is the maximum shiftOn 432 MHz the maximum shift is 15kHz The shift is upward on moonrise anddownward on moonset When the moon isdue south your own echoes will have noDoppler shift but stations located faraway will still be affected For schedul-ing the accepted practice is to transmitzero beat on the schedule frequency andtune to compensate for the Doppler shiftBe carefulmdashmost transmitters and trans-ceivers have a built-in CW offset Someradios read this offset when transmittingand others donrsquot Find out how your trans-mitter operates and compensate as re-quired

Random operation has become popularin recent years In the ARRL EME con-test many of the big guns will not evenaccept schedules during the contest peri-ods because they can slow down the paceof their contest contacts

EME Operating TimesObviously the first requirement for

EME operation is to have the moon visibleby both EME stations This requirementnot only consists of times when the moonis above the horizon but when it is actuallyclear of obstructions such as trees andbuildings It helps to know your exact EMEoperating window specified in the form ofbeginning and ending GHAs (Greenwich


2340 Chapter 23

Hour Angle) for different moon declina-tions This information allows two differ-ent stations to quickly determine if theycan simultaneously see the moon

Once your moon window is deter-mined the next step is to decide on thebest times during that window to sched-ule or operate Operating at perigee ispreferable because of the reduced pathloss Fig 2368 shows that not all perigeesare equal There is about a 06-dB differ-ence between the closest and farthestperigee points The next concern is oper-ating when the moon is in a quiet spot ofthe sky Usually northern declinationsare preferred as the sky is quietest at highdeclinations If the moon is too close tothe sun your array will pick up sun noiseand reduce the sensitivity of your re-ceiver Finally choosing days with mini-mal libration fading is also desirable

Perigee and apogee days can be deter-mined from the Astronomical Almanac byinspecting the tables headed ldquoSDrdquo (semi-diameter of the moon in minutes of arc)These semi-diameter numbers can be com-pared to Fig 2368 to obtain the approxi-mate moon distance Many computerprograms for locating the moon now givethe moonrsquos distance The expected bestweekends to operate on 432 MHz and thehigher bands are normally printed well inadvance in various EME newsletters

When the moon passes through thegalactic plane sky temperature is at itsmaximum Even on the higher bands this isone of the least desirable times to operateThe areas of the sky to avoid are the con-

Table 238432-MHz Procedure mdash 2frac12-Minute Sequence

Period 2 minutes 30 seconds

1 VE7BBG DE K2UYH2 K2UYH DE VE7BBG3 VE7BBG DE K2UYH TTT4 K2UYH DE VE7BBG MMM5 RM RM RM RM DE K2UYH K6 R R R R R DE VE7BBG SK

Table 237144-MHz Procedure mdash 2-Minute Sequence

Period 112 minutes 30 seconds1 Calls (W6XXX DE W1XXX)2 W1XXX DE WE6XXX TTTT3 W6XXX DE W1XXX OOOO4 RO RO RO RO DE W1XXX K5 R R R R R R DE W6XXX K6 QRZ EME DE W1XXX K

stellations of Orion and Gemini (duringnorthern declinations) and Sagittarius andScorpios (during southern declinations)The position of the moon relative to theseconstellations can be checked with infor-mation supplied in the Astronomical Alma-nac or Sky and Telescope magazine

Frequencies and SchedulingAccording to the ARRL-sponsored band

plan the lower edge of most bands is re-served for EME operation On 144 MHzEME frequencies are primarily between144000 and 144080 MHz for CW and144100 and 144120 MHz for SSB Ran-dom CW activity is usually between144000 and 144020 MHz In the US144000 to 144100 MHz is a CW sub-band so SSB QSOs often take place byQSYing up 100 kHz after a CW contacthas been established Because of the largenumber of active 144-MHz stationscoordinating schedules in the small EMEwindow is not simple The more activestations usually have assigned fre-quencies for their schedules

On 432 MHz the international EMECW calling frequency is 432010 MHzRandom SSB calling is done on 432015MHz Random activity primarily takesplace between 432000 and 432020 MHzThe greater Doppler shift on 432 MHzrequires greater separation between sched-ule frequencies than on 144 MHz Nor-mally 432000 MHz 432020 MHz andeach 5-kHz increment up to 432070 MHzare used for schedules

Activity on 1296 MHz is centered be-

tween 1296000 and 1296040 MHz Therandom calling frequency is 1296010MHz Operation on the other bands re-quires more specific coordination Activityon 33 cm is split between 902 and 903 MHzActivity on 2300 MHz has to accommodatesplit-band procedures because of the dif-ferent band assignments around the world

EME Net InformationAn EME net meets on 14345 MHz on

weekends for the purpose of arrangingschedules and exchanging EME informa-tion The net meets at 1600 UTC OSCARsatellites are becoming more popular forEME information exchange When ModeB is available a downlink frequency of145950 MHz is where the EME groupgathers On Mode L and Mode JL thedownlink frequency is 435975 MHz

Other ModesMost EME contacts are still made on

CW although SSB has gained in popularityand it is now common to hear SSB QSOs onany activity weekend The ability to workSSB can easily be calculated from Eq 1The proper receiver bandwidth (23 kHz) issubstituted SSB usually requires a +3-dBsignal-to-noise ratio whereas slow-speedCW contacts can be made with a 0-dB sig-nal-to-noise ratio Slow-scan television andpacket communication has been attemptedbetween some of the larger stations Suc-cess has been limited because of the greatersignal-to-noise ratios required for thesemodes and severe signal distortion fromlibration fading


Introduction to the CD-ROM Edition

Using this CD-ROM

Full-Text Searching

ARRL on the Internet

Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols

The ARRLmdashAt Your Service

Chapter 1mdashWhat is Amateur (Ham) Radio

Hobby of Diversities

Your License

US Amateur Bands

Ham Radio Action

Getting Started

Governing Regulations

Resources

Glossary

Chapter 2mdashActivities in Amateur Radio

Awards

Contests

Nets

Amateur Radio Education

Emergency Communications

Specialized Communications

Chapter 3mdashSafety

Antenna and Tower Safety

Power Lines

Electrical Wiring around the Shack

LightningTransient Protection

Grounds

Project An Earth-Continuity Tester

Station Power

FCC RF-Exposure Regulations

Safe Homebrewing

RF Radiation and EMF Safety

Other Hazards in the Ham Shack

Chapter 4mdashElectrical Fundamentals

DC Circuits and Resistance

Series and Parallel Resistances

Power and Energy

Circuits and Components

AC Theory and Reactance

Frequency and Period

Capacitance and Capacitors

Inductance and Inductors

Quality Factor (Q) of Components

Calculating Practical Inductors

Ohmrsquos Law for Reactance

Impedance

Resonant Circuits

Transformers

Chapter 5mdashElectrical Signals and Components

Analog Glossary

Analog Signal Processing

Analog Devices

Practical Semiconductors

Transistor Amplifier Design

Digital Fundamentals

Number Systems

Physical Representation of Binary States

Combinational Logic

Sequential Logic

Digital Integrated Circuits

Computer Hardware

Chapter 6mdashReal-World Component Characteristics

Lumped vs Distributed Elements

Low-Frequency Component Models

Components at RF

Thermal Considerations

The Thermistor in Homebrew Projects

Low-Frequency Transistor Models

Chapter 7mdashComponent Data and References

Component Values

Component Markings

Inductors and Core Materials

Other Sources of Component Data

Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References

GeneralElectronicsComputers

ComponentsEquipment

AntennasTransmission Lines

Modes

Operating and Interference

Message Handling

Chapter 8mdashCircuit Construction

Shop Safety

Tools and their Uses

Project A Deluxe Soldering Station

Project Soldering-Iron Temperature Control

Electronic Circuits

Surface Mount Construction Techniques

From Schematic to Working Circuit

Microwave Construction Techniques

High-Voltage Techniques

Mechanical Fabrication

Chapter 9mdashModes and Modulation Sources

Issues Common to all Transmission Modes

Emission Classifications

Emission Modulation and Transmission Characteristics

Major Modulation Systems

Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems

Chapter 10mdashOscillators and Synthesizers

How Oscillators Work

Phase Noise

Oscillator Circuits and Construction

VHF and UHF Oscillators

Frequency Synthesizers

Phase-Locked Loops

Synthesizer in an MFHF Transceiver

Trends in Oscillator Applications

Chapter 11mdashMixers Modulators and Demodulators

The Mechanism of Mixers and Mixing

Practical Building Blocks

Testing and Calculating IMD in Receivers

Chapter 12mdashRF and AF Filters

Basic Concepts

Filter Synthesis

Designs using SoftwareSVC Tables

Chebyshev Filter Design

Quartz Crystal Filters

Monolithic Crystal Filters

SAW Filters

Transmission-Line Filters

Helical Resonators

Active Filters

Project Crystal Filter Evaluation

Project Band-Pass Filters for 144 or 222 MHz

Project High-Performance Passive CW Filter

Project Broadcast Band Rejection Filter

Project A Wave Trap for Broadcast Stations

Project Second-Harmonic-Optimized LP Filters

Project The Diplexer Filter

Chapter 13mdashEMIDirection Finding

The Scope of the Problem

Responsibility

EMC Fundamentals

Cures

TVI Troubleshooting Chart

Amateur HarmonicsCATV Chart

Project Finding Shack Noise Sources

Radio Direction Finding

Project The Simple Seeker

Project Active Attenuator for VHF-FM

Chapter 14mdashReceivers and Transmitters

A Single-Stage Building Block

Negative Feedback in RF Design

Receiver Design Techniques

The Superheterodyne Receiver

VHF and UHF Receivers

Project GaAsFET Preamp for 430 MHz

Project Microwave Receiver for 10 GHz

Transmitter Design

Project A Rock-Bending Receiver for 7 MHz

Project A Wideband MMIC Preamp

Project A Binaural I-Q Receiver

Project A Superregenerative Receiver with Squelch

Project A Broadband HF Amp using MOSFETS

Project A Drift-Free VFO

Project A Simple Regenerative HF Receiver

Chapter 15mdashTransceivers Transverters and Repeaters

Transceiver Example

Project The Norcal SierramdashAn 80-15 M CW Transcei

Project A 10-Watt SSB Transceiver for 60-M Band

Transverters

Repeaters

Chapter 16mdashDSP and Software Radio Design

DSP Fundamentals

DSP Algorithms for Radio

Analytic Signals and Modulation

Digital Speech Processing

Interference-Reduction Techniques

Fourier Transforms

Radio Architectures for DSP

Software Radios

Hardware for Embedded DSP Systems

DSP System Software

DSP Projects

Project A Decimation

Project B FIR Filter Design Variations

Project C Analytic Filter Pair Generation

Project D Newtonrsquos Method for Square Roots

Project E A Fast Square-Root Algorithm

Project F A High-Performance DDS

Project G Fast Binary Multiplier in High-Speed CMOS Logic

Chapter 17mdashPower Supplies

Glossary

Alternating-Current Power

Rectifier Types

Rectifier Circuits

Filtration

Regulation


Batteries and Charging

Emergency Operations

Power-Supply Projects

Project Series-Regulated 45- to 25-V Supply

Project 138-V 40-A Switching Supply

Project 28-V High-Current Supply

Project Commercial-Quality High-Voltage Supply

Project Micro M+ Charge Controller

Project The UPSmdashA Universal Supply

Project A Portable Power Supply

Chapter 18mdashRF Power Amplifiers

Types of Power Amplifiers

Design Examples

Project 3CX1500D7 RF Linear Amplifier

Project A 6-Meter kW Amplifier

Project A 144-MHz Amplifier

Chapter 19mdashStation Layout and Accessories

Fixed Stations

Mobile and Portable Installations

Project Tick-2mdashA Tiny CMOS Keyer 2

Project Vintage Radio TR Adapter

Project Quick and Easy CW with your PC

Project An Expandable Headphone Mixer

Project A Simple 10-Minute ID Timer

Project Audio Break-Out Box

Project An SWR Detector Audio Adapter

Project PC Voltmeter and SWR Bridge

Project Tandem MatchmdashAn Accurate Directional Wattmeter

Project Automatic Antenna Switch for Yaesu or ICOM

Project A Trio of TransceiverComputer Interfaces

Project Computer-Controlled Two-Radio Switchbox

Project TR Time-Delay Generator

Project A Switched Attenuator

Project Simple QRP TR Changeover

Project QRP L-Match ATU

Project QRP T-Match ATU

Project An Ugly Transformer for Heavy-Load Stations

Chapter 20mdashPropagation of RF Signals

Fundamentals of Radio Waves

Propagation Summary by Band

MUF Prediction

Propagation in the Troposphere

Extraterrestrial Propagation

Chapter 21mdashTransmission Lines

Basics

Matched Lines

Reflections on the Smith Chart

Matching the Antenna to the Line

Matching the Line to the Transmitter

Loads and Balancing Devices

Waveguides

Chapter 22mdashAntennas

Antenna Polarization

Dipoles and the Half-Wave Antenna

Project 135-FT Multiband Dipole

Antenna Modeling by Computer

Project A 4015-M Dual-Band Dipole

Project K8SYL 7510-M Dual-Band Dipole

Project W4RNL Inverted-U Antenna

Project Two W8NX Multiband Coax-Trap Dipoles

Vertical Antennas

Optimum Ground Systems for Vertical Antennas

Project Dual-Band Verticals for 1740M or 1230M

Inverted L and Sloper Antennas

Project 18-MHz Inverted L

Project Half-Wave Vertical Dipole (HVD)

Project The Compact Vertical Dipole (CVD)

Project All Wire 30-M CVD

Yagi and Quad Directive Antennas

Quad Antennas

Project Five-Band Two-Element HF Quad

Project Simple Quad for 40 M

Project Simple Loop for 28 MHz

HF Mobile Antennas

VHFUHF Antennas

Project Simple Portable Groundplane Antenna

Project Dual-Band Antenna for 146446 MHz

Project A Quick Antenna for 223 MHz

Project An All-Copper 2-M J-Pole

VHFUHF Yagis

Project 3- and 5-Element Yagis for 6 M

Project A Medium Gain 2-M Yagi

Chapter 23mdashSpace Communications

An Amateur Satellite Primer


Project Single Brick L-Band Amplifier

Project Double Brick L-Band Amplifier

Project Parabolic Dish Construction

Project Helix Feed for an Offset Dish

Project Integrated AO-40 Antenna System

Glossary of Satellite Terminology

Earth-Moon-Earth (EME)

Chapter 24mdashWeb Wi-Fi Wireless and PC Technolo

The World Wide Web (www)mdashThe Internet

Hamrsquos Guide to Useful Internet Sites

GlossaryWireless Fidelity (Wi-Fi)

Glossary of Wireless Technology

Wireless Technology

Personal Computers in the Shack

Mode-Specific Software

Chapter 25mdashTest Procedures

Test and Measurement Basics

DC Instruments and Circuits

AC Instruments and Circuits

Project The Microwatter

Frequency Measurement

Project Marker Generator with Selectable Output

Project A Dip Meter with Digital Display

Other Instruments and Measurements

Project A Wide-Range Audio Oscillator

Project Measure Inductance and Capacitance with a DVM

Oscilloscopes

Project HF Adapter for Narrow Bandwidth Scopes

Project A Calibrated Noise Source

Project Signal Generator for Receiver Testing

Project Hybrid Combiners for Signal Generators

Project Compensated Modular RF Voltmeter

Receiver Performance Tests

Transmitter Performance Tests

Chapter 26mdashTroubleshooting and Repair

Safety First

Where to Begin

Testing within a Stage

Look for the Obvious

Typical Symptoms and Faults

Troubleshooting Hints

After the Repairs

Professional Repairs

Back Material

Advertising

ARRL Membership Form

Index

About the ARRL

Cover III

Cover IV

Template Packages

232 Chapter 23

Fig 233mdashA linear transponder acts much like a repeater except that it relays anentire group of signals not just one signal at a time In this example the satelliteis receiving three signals on its 23-cm uplink passband and retransmitting themon its 13-cm downlink passband

as 5 kHz) were transmitted to the satellitethe satellite would retransmit all three sig-nalsmdashstill separated by 5 kHz each (seeFig 233) Just like a terrestrial repeaterthe retransmissions take place on frequen-cies that are different from the oneson which the signals were originallyreceived

Some linear transponders invert theuplink signals In other words if you trans-

Fig 232mdashUO-36 captured this image ofa well-known city in the western USNeed a hint Think ldquoCaesarrsquos Palacerdquo

Tired of the Same Old QSOs Break out of Orbit and Set your Course for theldquoFinal Frontierrdquo

Satellite-active hams comprise a relatively smallsegment of our hobby primarily because of an unfortu-nate fiction that has been circulating for many yearsmdashthemyth that operating through amateur satellites is overlydifficult and expensive

Like any other facet of Amateur Radio satellite hamming isas expensive as you allow it to become If you want to equipyour home with a satellite communication station that wouldmake a NASA engineer blush it will be expensive If you wantto simply communicate with a few low-Earth-orbiting birdsusing less-than-state-of-the-art gear a satellite station is nomore expensive than a typical HF or VHF setup In manycases you can communicate with satellites using your presentstation equipmentmdashno additional purchases are necessary

Does satellite hamming impose a steep learning curve Not

really You have to do a bit of work and invest some brainpower to be successful but the same can be said ofDXing contesting traffic handling digital operating or anyother specialized endeavor You are after all communi-cating with a spacecraft

The rewards for your efforts are substantial makingsatellite operating one of the most exciting pursuits inAmateur Radio There is nothing like the thrill of hearingsomeone responding to your call from a thousand milesaway and knowing that he heard you through a satellite(The same goes for the spooky spellbinding effect ofhearing your own voice echoing through a spacecraft asit streaks through the blackness of space) Satellitehamming will pump the life back into your radioexperience and give you new goals to conquer

mit to the satellite at the bottom of theuplink passband your signal will appearat the top of the downlink passband Inaddition if you transmit in lower sideband(LSB) your downlink signal will be inupper sideband (USB) See Fig 234 Sat-ellite passbands are usually operated ac-cording to the courtesy band plan asshown Transceivers designed for satelliteuse usually include features that cope withthis confusing flip-flop

Over the years the number of amateurbands available on satellites has in-creased To help in easily identifyingthese bands a system of ldquoModesrdquo hasbeen created In the early years referenceto these Modes was by a single letter(Mode A Mode B etc) but with thelaunch of more satellites the opportuni-

ties greatly increased and it was neces-sary to show both the uplink and down-link bands See Table 231 SatelliteOperating Modes

Linear transponders can repeat any typeof signal but those used by amateur satel-lites are primarily designed for SSB andCW The reason for the SSB and CW pref-erence has a lot to do with the hassle ofgenerating power in space Amateur sat-ellites are powered by batteries which arerecharged by solar cells ldquoSpace ratedrdquosolar arrays and batteries are very expen-sive They are also heavy and tend to takeup a substantial amount of space Thanksto meager funding hams donrsquot have theluxury of launching satellites with largepower systems such as those used by com-mercial birds We have to do the best we























234 Chapter 23







































236 Chapter 23






















FO-29 145900-146000 435800-435900435795 (CW beacon)

RS-15 145858-145898 29354-29394VO-52 435225-435275 145875-145925


AO-16 14590 92 94 96 437051NO-44 145827 144390


GO-32 890145850 435225

FM Voice Repeaters














238 Chapter 23
























2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages






















234 Chapter 23







































236 Chapter 23






















FO-29 145900-146000 435800-435900435795 (CW beacon)

RS-15 145858-145898 29354-29394VO-52 435225-435275 145875-145925


AO-16 14590 92 94 96 437051NO-44 145827 144390


GO-32 890145850 435225

FM Voice Repeaters














238 Chapter 23
























2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages


























236 Chapter 23






















FO-29 145900-146000 435800-435900435795 (CW beacon)

RS-15 145858-145898 29354-29394VO-52 435225-435275 145875-145925


AO-16 14590 92 94 96 437051NO-44 145827 144390


GO-32 890145850 435225

FM Voice Repeaters














238 Chapter 23
























2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages





FO-29 145900-146000 435800-435900435795 (CW beacon)

RS-15 145858-145898 29354-29394VO-52 435225-435275 145875-145925


AO-16 14590 92 94 96 437051NO-44 145827 144390


GO-32 890145850 435225

FM Voice Repeaters














238 Chapter 23
























2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages

238 Chapter 23
























2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages













2310 Chapter 23



























2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages















2312 Chapter 23







Power Amplifiers


Antennas


Rotators


Other Suppliers
























2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages

















2314 Chapter 23























2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages














2316 Chapter 23



























2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages
















2318 Chapter 23































2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages















2320 Chapter 23

























2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages














2322 Chapter 23
































2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages




















2324 Chapter 23



























2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages











2326 Chapter 23


































2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages
















2328 Chapter 23






















































































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages











































2330 Chapter 23






























































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages






































2332 Chapter 23








































QST Sep 1993 p 104




QST Dec 1993 p 89






































2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages























2334 Chapter 23




































Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages












Power at the array





2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages

2336 Chapter 23






s10n KBTlog10P (2)


ture (K)



























EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages





EcosKEsin

Ftan (5)


Ccos (6)









382cos006175061795

Ftan

= 076489




Ccos







D = ndash150745 times SD + 474332


almanac








2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages

2338 Chapter 23







































2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages


























2340 Chapter 23






















Using this CD-ROM

Full-Text Searching


Front Material

Cover I (Front)

Cover II

Table of Contents

Foreword

Amateurrsquos Code

Schematic Symbols




Your License

US Amateur Bands

Ham Radio Action

Getting Started


Resources

Glossary


Awards

Contests

Nets






Power Lines



Grounds


Station Power


Safe Homebrewing






Power and Energy









Impedance

Resonant Circuits

Transformers


Analog Glossary


Analog Devices




Number Systems


Combinational Logic

Sequential Logic


Computer Hardware




Components at RF





Component Values

Component Markings



Semiconductors

Integrated Circuits

Vacuum Tubes

Other

References


ComponentsEquipment


Modes


Message Handling


Shop Safety




Electronic Circuits











Internetworking

Radio Control (RC)

Voice Modes

Image Modes

Spread Spectrum

Multimedia Systems



Phase Noise




Phase-Locked Loops








Basic Concepts

Filter Synthesis





SAW Filters


Helical Resonators

Active Filters










Responsibility

EMC Fundamentals

Cures















Transmitter Design









Transceiver Example



Transverters

Repeaters


DSP Fundamentals





Fourier Transforms


Software Radios


DSP System Software

DSP Projects









Glossary


Rectifier Types

Rectifier Circuits

Filtration

Regulation














Design Examples





Fixed Stations























MUF Prediction




Basics

Matched Lines





Waveguides










Vertical Antennas









Quad Antennas




HF Mobile Antennas

VHFUHF Antennas





VHFUHF Yagis


















Wireless Technology














Oscilloscopes









Safety First

Where to Begin





After the Repairs


Back Material

Advertising


Index

About the ARRL

Cover III

Cover IV

Template Packages