presented by rob ewert ve1ks · • mobile radio range is 20 km to 40 km • ht range is 2 km to 5...

Repeaters and Linking

Presented by

Rob Ewert VE1KS

Repeaters and Linking My Background Repeaters

• What are they?• Why do we need them?• How do they work?• How are they controlled• What kinds are there?• Where are they?• What do I need to know to use them• Digital Voice Modes

Linking Repeaters

• Why do we do it?• How do we link repeaters?• How are links controlled• Linking in NS (MAVCOM, IRLP, Echolink)

Operating Etiquette

• Repeater usage etiquette• Linking etiquette

\ Introduction /


What are they?

• They re-transmit, in real time, any signal received

• Antenna, duplexer, receiver, transmitter & controller

• Some times multiplexers are used instead of duplexers

• Coverage is usually circular in pattern

• Range can be 250 Km or more, station to station

• Repeater transmit power is typically 20W to 100W

• 28, 50, 220, 146, 440, 1200 Mhz or cross-band

• Can be open or closed

\ Repeaters /


This is VE1PAR in the Parrsboro area


Why do we need them?

• Mobile radio range is 20 Km to 40 Km

• HT range is 2 Km to 5 Km

• Repeaters extend the usable range of our mobiles, HT’s

• They can be a common gathering place for hams that are spread out, geographically

• They can provide important club announcements

• They can provide time, date, weather info

• They can provide reliable emergency communications

\ Repeaters /

Repeaters and Linking How do they work?

• A signal, on Freq A, is received in the repeater antenna

• The signal goes down the feed line to the receive port of the duplexer

• From the receive port of the duplexer, the signal feeds the receiver radio tuned to Freq A

• Freq A is demodulated and the audio is fed to a repeater controller on Port 1 interface card

• The audio is routed back out Port 1 to a transmit radio where it is modulated and transmitted on Freq B.

• The transmitted RF is sent to the transmit port of the duplexer where it is combined with the receive signal and fed on to the repeater antenna

• Both receiving Freq A and transmitting Freq B, usually use the same antenna

\ Repeaters /


Receiver

Transmitter

Controller

Port 1

RX COSRX Audio

TX PTTTX Audio


How are they controlled?

• A repeater controller device is used• Consists of micro-processor board and interface cards• DTMF tones allow users to control certain functions• RS-232 port allows for programming• Inserts ID’s, hangtimes, decode/encode CTCSS tones,

announcements on top of repeated audio• They route the control signals required to key and

unkey the transmitter• They time and time limit the received and re-

transmitted signals.• They interconnect audio and control signals between

I/F cards for the purposes of linking• They can read external sensors like temp and door

alarms• They can interface with the phone system

\ Repeaters /

Repeaters and Linking\ Repeaters /

How are they powered?

- AC (Hydro/Utility)

- AC (Utility w/ backup generator and/or UPS)

- Solar powered with 12V battery banks

- Wind turbine powered with 12V battery banks

What kinds are there?

- Commercially built (Motorola, GE, Yaesu)

- Mixture of components (Motorola, GE, Link)

- Homebrew (power supply and controller)


Where are they located?

• Spread out geographically

• Often located on high ground

• Often located at commercial sites with other radio systems

• Can be found on Repeater lists, MAVCOM codes, etc

• ARRL Repeater Handbook

• URL: ve1cra.net (under repeater linking)

• Google maps

• Ask local hams

Maritime VHF Repeaters

Maritime UHF Repeaters


What do I need to know to use them?

• What is the rough coverage area of the repeater• What is the frequency I should listen on• What is the offset frequency between RX and TX• What are Sub-audible tones• CTCSS (Continuous Tone-Coded Squelch System)• Superimposes a sub-audible freq on the signal• DCS (Digital Coded Squelch)• Superimposes a continuous stream of FSK digital data,

at about 131 baud, on the TX signal• 1750 Hz tone burst (European, but being phased out)• Identifiers (CW, Artificial Voice or DVR)• Different courtesy tones used depending on status• DTMF user codes (Dual Tone Multi Frequency)• DTMF muting and falsing


Digital Voice Modes

• DMR (Digital Mobile Radio Standard)– Mototrbo (Motorola) (Springhill)

• D-Star (Icom) (Church Lake & Antigonish)

• Wires/Fusion (Yaesu) (Southampton, Truro, Antigonish and Yarmouth)

• Proprietary in nature

• Many systems can autosense and operate in both FM analog and digital modes

• Encodes and decodes audio as a digital bit stream

• http://www.maritimeamateur.ca/digitalradio.htm


Why do we link repeaters?

• To increase the geographical range of repeaters

• To be able to communicate to others in other provinces and countries

• To be able to pass emergency or relevant communications between regions

• To link together hams with common interests

\ Linking Repeaters /


How do we link repeaters?

• Terrestrial RF (MAVCOM)

• Microwave RF (NB IRG System)

• Telephone company leased circuits (TMRS)

• Internet (IRLP or Echolink)

\ Linking Repeaters /

Repeaters and Linking\ Linking Repeaters /

How are links controlled?

• Repeater controllers control the link radios

• Linking uses DTMF on and off codes

• 3 or 4 digit codes with an asterisk or pound

• Some systems use just numbers

• Off codes can sometimes be one unique code (73) or a regular link code

• Repeater controllers are programmed to respond to DTMF commands that connect or disconnect that repeater to the link system


What do I need to know to use the linking system?

• Where are you right now?

• Where do I want to link to?

• What are the DTMF codes that are needed to link?

• Entering DTMF codes, listening for the right audio responses

• Timeout timers on links to be aware of

• Network propagation delays

• OCTD (One Code To Destination)

• DTMF regeneration over links


MAVCOM

• Maritime Amateur Voice Communications System• Terrestrial Repeater RF linking over UHF frequencies• Consists of UHF hubs and UHF trunked sites• Link sites are rarely over 60 miles apart• 60% of MAVCOM is half duplex, 40% is full duplex• Uses 4 digit DTMF on and off codes• Link codes are executed when you unkey (Enter)• Audio, voice or CW link status messages are sent to

indicate link status• Different courtesy tones can be used when linked• Link inactivity timer is generally 5 minutes• Link activity timer is generally 3 minutes• More than one repeater can be linked at a time• New links always being added (Work in progress)• Link codes follow the Coordinated Dialing Plan (106*

on, 107* off)


Controller

Controller

Port 1

Port 2

Port 1

Port 2

Basic Link Between 2 Repeaters

VE1HNS

VE1PSR

Repeaters and LinkingMAVCOM UHF BACKBONE

Port 2 Port 3Port 1

Controller

VE1HNS VE1MHR

VE1PSR

TRUNK LINK SITE


Controller

VE1KEJVE1VO

VE1LCA HUB

HUB LINK SITE

Port 1

Port 2

MAVCOM UHF BACKBONE

VE1BO

VE1LCA RPTR


IRLP (www.irlp.net)

• Uses the Internet for linking repeater systems• Creates a secure, full duplex audio stream between

repeater systems using VOiP and PGP keys• The connection point between repeater and the

Internet is called a “Node”• Many nodes can be joined together on the internet

using a “Reflector” (party line)• There are 2900 nodes and 31 reflectors• Uses a 4 digit on code and a common off code (73)• Node software runs on the Linux operating system• Requires any old computer and the IRLP interface

board (installs inside computer)• Node 2050 (VE1NSG/VE1HNS) configuration• Node locations and status can be found online at:

http://status.irlp.net• You can add custom codes and features


Controller

Controller

Port 1

Port 2

Port 1

Port 2

Halifax, Canada – VE1HNS

Basel, Switzerland - HB9TVW Internet


Echolink

• Uses the Internet for linking repeaters and PCs

• Security is through a validation process and then username/password

• Windows based, but packages available on Linux and MAC

• Hard to get an exact number of nodes

• Uses a 4, 5 or 6 digit on code and a common off code

• Interface uses WB2REM, VA3TO or Rigblaster

• EchoIRLP nodes (not able to cross-connect)

Repeaters and Linking\ Operating Etiquette /

Repeaters

• Listen, Listen, Listen!!!!• Regulations state that you must know what frequency

you are operating on, not just the callsign• Unsure the repeater is clear? Please ask on air.• Use callsigns only at the beginning and end of a

conversation. Only repeat every 20 minutes• Please wait for the courtesy tone or wait 2 seconds

before replying. A repeater drop is not needed.• VERY IMPORTANT When replying, press the PTT,

wait at least 2 seconds BEFORE speaking• Speak clearly and loudly, holding the mic 2-3 inches

from your mouth. Phonetics are not generally required unless noisy conditions prevail

• Avoid using repeaters when you are in simplex range• Proper mobile/portable identification terms• Turn OFF any background audio sources• DO NOT Kerchunk repeaters without identifying


Repeaters (Group conversations)

• If a group of people are talking, only jump in if the conversation has become general in nature and you have something to add that is relevant

• You acknowledge all others in the conversation• DO NOT change the current topic• DO NOT ignore others in the group• DO leave long pauses between transmissions, allowing

others to join in or bow out • DO join the QSO by giving your callsign only• DO NOT join by saying “break” or “contact”• Give preference to mobiles or portables• Keep conversations to 15-20 minutes• Always turn the conversation over to someone specific

in the group• FM capture effect


MAVCOM

• Be sure the repeater is clear and available. Get on the radio and ask if necessary

• Give your callsign and state your intentions. Then dial the appropriate DTMF codes

• If not using OCTD, pause after dialing the first on code that puts you on the UHF backbone, wait for link on status message

• If system is clear, announce your callsign, intentions and dial your destination code. Listen for link status message before proceeding.

• IMPORTANT Leave several seconds between transmissions and when keying up to talk, wait at least two seconds BEFORE speaking

• If you end up in a local repeater conversation, turn off any links in use, first!


MAVCOM

• To downlink, give your callsign, intentions and dial the DTMF off code. Then announce locally that you are clear of the link system once you have heard the link status messages.

• Link status messages. What should you hear?

• If unsuccessful or in doubt try again

• You can’t break the system

Repeaters and Linking\ The End /

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presented by rob ewert ve1ks · • mobile radio range is 20 km to 40 km • ht range is 2 km to 5...

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