the ionogram and radio propagation · 2017-12-21 · the ionogram and radio propagation by terry g....

The Ionogram and Radio Propagation

by

Terry G. GlagowskiW1TR / AFA1DI

By Terry G. Glagowski / W1TR / AFA1DI - 9/29/2017 9:46 AMExcerpts from a presentation by Tom Carrigan / NE1R / AFA1ID

Knowledge of Radio Propagation is important to the operations of HF MARS nets.It enables the NCS to choose the proper frequency so that the net can reach the most stations.

If the chosen frequency is too high, skip zones may prevent reaching close in stations.If the chosen frequency is too low, distant stations may be weak or unreadable.

Radio checks on the alternative frequencies is the best indication of useable propagation.Use of Ionograms created by Digisondes can help in deciding the proper frequency.

When the Internet is available, Ionograms can be viewed online at various sites.

Introduction• Radio Propagation

– Ground Wave– Skywave– NVIS

• Ionosphere Layers– Creation of Ionosphere– D Layer: Absorption– E Layer: Sporadic Es Skywave– F Layers: F1, F2 Primary Skywave– FoF2 Critical Frequency: NVIS– MUF Maximum Useable Frequency: DX

• Solar Behavior– 11 year Sunspot Cycles– SSN– SFI– A Index– K Index– Solar Flares, CME

• Ionogram– Digisondes generate Ionograms– Interpretation of the Ionogram

• How to Choose Net Frequency– Geography– MUF and FoF2

Radio Propagation

http://www.frankswebspace.org.uk/ScienceAndMaths/physics/physicsGCE/images/transmissionPaths.gif

Freq > MUFMaximum Frequency

Reflected by Ionosphere

Freq < MUF

Critical FrequencyFoF2 = MUF

For NVIS

Ionospheric Layers

http://image.slidesharecdn.com/radiopropagation101-141231201444-conversion-gate01/95/radio-propagation-101-18-638.jpg?cb=1420058206

Ionospheric Layers – D Layer


0-5 mHz

5-10 mHz10-30 mHz

Ionospheric Layers – E Layer


30-200 mHz

Ionospheric Layers – F Layers


Ionospheric Layers – Frequencies


Skywave Propagation

Freq > MUF

Freq < MUF

NVIS when Skip Distance = 0, when F < FoF2 Critical Frequency

http://images.tutorvista.com/content/communication-systems/ionosphere-effects.gif

Solar Indices

http://image.slidesharecdn.com/cycle24hbarctalk-150128054239-conversion-gate02/95/cycle-24-hbarc-talk-7-638.jpg?cb=1422426843

Solar Indices


Sunspot Cycles


Geomagnetic – A Index


Geomagnetic – K Index


CME – Coronal Mass Ejection


Solar and Geomagnetic Indices


http://www.hamqsl.com/solar101pic.php


Digisonde

Apparatus to generate Ionogramsand calculate FoF2 and MUFhttp://digisonde.com/images/Digisonde-HF-Radar-System2.jpg

Ionogram - Notional

http://www.astrosurf.com/luxorion/Radio/ionogram-dwg.gif

Ionogram - Legend

https://upload.wikimedia.org/wikipedia/commons/a/a7/HAARP_ionogram.png

Ionogram - Terms

http://www.g0lfp.com/ionograms/ursi_codes.html

URSI Ionospheric Parameter Codes

F Layer ParametersParameter DescriptionfoF2 F2 layer o-mode (ordinary) critical frequency.fxF2 F2 layer x-mode (extraordinary) critical frequency.fzF2 F2 layer z-mode critical frequency.M3000F2 F2 layer M factor (the ratio of the maximum usable frequency divided by the critical frequency).h'F2 F2 layer o-mode minimum virtual height.hpF2 An estimate of the true height of the F2 layer (measurement of the ordinary mode virtual height at a frequency of 83.4% of the foF2).h'Ox F layer minmum virual height of the x-mode trace at a frequency equal to the foF2.MUF3000F2 F2 layer maximum usable frequency for 3000km path.foF1 F1 layer o-mode critical frequency.fxF1 F1 layer x-mode critical frequencyh'F1 F1 layer o-mode minimum virtual height.h'F F layer o-mode minimum virual height.MUF3000F1 F1 layer maximum usable frequency(see code 07).

E Layer ParametersParameter DescriptionfoE E layer o-mode critical frequency.foE2 E2 layer o-mode critical frequency (when it occurs it is between the normal E and F1 layers).h'E E layer o-mode minmum virual height.h'E2 E2 layer o-mode minimum virtual height.

Es Layer ParametersParameter DescriptionfoEs Es layer hightest o-mode frequency are which a mainly continuous Es trace is observed.fxE Es layer highest x-mode frequency are which a mainly continuous Es trace is observed.fbEs The blanketing frequency of layer used to derive foEs.ftEs Top frequency of the Es trace (any mode).

FoF2 Map

http://www.sws.bom.gov.au/Images/HF%20Systems/Global%20HF/Ionospheric%20Map/WorldIMap.gif

4 to 5 MHz

Ionogram - Actual

FoF2

http://umlcar.uml.edu/WatchIt/latestIonogram.html

MUF

FoF2

E Layer

D LayerAbsorption

Multiple F2Reflections

FxF2 Extraordinary

F2

F2

F2

FoF2 / MUF Indicate2.5 MHz NVIS, Absorption?3.3 MHz NVIS, Absorption?4.6 MHz NVIS5.8 MHz 700 KM Skip7.6 MHz 1200 KM SkipE Layer may cause Absorption

How to Choose a Net FrequencyAlways Confirm Prediction with RADIO CHECK Before NetRegion Nets• Check Ionogram for FoF2 frequency• Choose highest frequency <= FoF2, where there will be NO SKIP ZONE

Division Nets (RGN 1,2,3)• Determine the geographical region of the net operations• Check the Ionogram to see what the FoF2 and skip distances will be• Frequencies slightly higher than FoF2 will work somewhat due to ground wave• If multiple Net Control Stations (NCS) are available

then a small to moderate skip zone can be tolerated (less than 400 km)and therefore a somewhat higher frequency can be used

• During daytime, absorption by D and E layers can be a factorso using the highest workable frequency

TransGlobal Net• Choose a frequency less than the MUF for the geographical area

but high enough to avoid absorption during the day by the D layer• Check the Ionogram to see what the MUF, FoF2, and skip distances will be• Since there will be a skip zone,

multiple NCS stations will be required: West, East, and Central.

USAF MARS NE Division, Regions 1,2,3

NVIS vs DX AntennasNVIS Antenna

High Angle of Radiation

DX AntennaLow Angle of Radiation

Vertical

Yagi

Low Dipole or Horizontal Loop

Propagation SitesA-Index, K-Index, SFI SummaryCONUS HF Band ConditionsNOAA IonogramMillstone Hill IonogramWallops Is IonogramLatest IonogramsIonogram Explanation (Wikipedia)Understanding Ionograms – G0LFPDX MapsIonospheric Map – Australian Space Weather ServicesQuick Guide to HF Propabation Using Solar Indices (N2LVI)HF Propagation Tools (N0NBH)K-Index (WikiPedia)Space Weather Prediction Center (NOAA)Space Weather (.com)Solar Hamhttp://car.uml.edu/common/DIDBFastStationList - List of Ionosode Stationshttp://www.sws.bom.gov.au/HF_Systems/6/5 - FoF2 Map


http://www.bandconditions.com/

https://www.ngdc.noaa.gov/stp/iono/ionogram.html

https://192.52.62.251/



https://en.wikipedia.org/wiki/Ionogram

http://www.g0lfp.com/ionograms/index.php

http://www.dxmaps.com/

http://www.ips.gov.au/HF_Systems/6/5

http://www.qsl.net/w2vtm/hf_solar.html

http://www.hamqsl.com/solar.html

https://en.wikipedia.org/wiki/K-index

http://www.swpc.noaa.gov/

http://www.spaceweather.com/

http://www.solarham.net/

http://car.uml.edu/common/DIDBFastStationList

http://www.sws.bom.gov.au/HF_Systems/6/5

Conclusion• Many factors regarding solar conditions

affect the ionosphere,and the magnetosphere,which affect radio propagation.– Time of Day– Day of Month (28 day rotation of sun)– Time of Year– Sunspot Cycle– Solar Flares– Geomagnetic Storms

• The best indication of good propagation is an actual radio check.

• Use of solar and geomagnetic indicesand ionograms,can greatly aid in the choice of the best frequency for net operations.

Extra Slides

The Ionosphere• The Ionosphere is a plasma shell of electrons, positive ions,

and molecules that surrounds the earth• The Ionosphere is created by ultraviolet radiation from the sun,

which ionizes the molecules of the atmosphere• Ionization is the process of ultraviolet photons transferring energy to a molecule,

thereby causing the electron and the positive ion to separate• Recombination is the reverse process, where a photon is emitted

when an electron recombines with the positive ion randomly and spontaneously• The electron density is determined by the

relative ionization and recombination rates when they are in equilibrium• The critical frequency is dependent on the electron density

at any given region: latitude, longitude, altitude, of the ionosphere• The maximum usable frequency for a given distance is dependent on

the critical frequency and critical angle • Factors affecting ionization include:

• Time of day (daylight vs darkness)• Day of month (28 1/2 day solar rotation), sunspots, flares point towards or away from earth• Time of year (summer vs winter vs fall and spring), amount of daylight and ionization• Solar Cycle (solar flux, sunspot number)• Solar Flares (unpredictable), proton and X-Ray events• Solar Wind creating Geomagnetic Storms

PROTON

ELECTRON

NEUTRON

PHOTONFREE

ELECTRON

Ionization and RecombinationIonization

occurs withsolar radiation (uv)

Recombinationoccurs randomly, spontaneously

proportional to density

PROTON

ELECTRON

NEUTRON

PHOTON

FREEELECTRON

Photon energy is proportional to frequency,Inversely proportional to wavelength.Units are in electron volts.Energy eV = 1.2398 / wavelength um.Minimum energy of ultra violet wavelengthIs needed to cause ionization.Ultraviolet is 10 – 400 nm.Or 3.1 – 124 eV.X-Rays have higher energy.

Ionospheric Layers

http://www.sws.bom.gov.au/Images/Educational/Other%20Topics/Radio%20Communication/ionosphere.png

Radio properties of the ionosphere,i.e. critical frequency, are determined by electron density, which is related to ionization rate, which depends on solar radiation.

Ionospheric Layers – Heights


Multi-Hop Propagation (DX)

http://www.astrosurf.com/luxorion/Radio/propagation-multi-hop-sky-waves.jpg

Radiation Angle Affects DX Performance

Fewer Hops

Attenuation Proportional to Number of Hops

Multi-Path Propagation (QSB)

http://www.wulfden.org/NVQS/PropStuff/img019.gif

Changing ionosphere location causes QSB fading

Can be caused by magnetic storms

Sporadic-E VHF Propagation

http://www.astronomie.be/radioastronomie/images/Sporadic%20E.gif

Also sometimes on 28 mHz and 144 mHz

Ionogram - Actual

FoF2


Skip Distance

MUF

FoF2

FoF2 / MUF Indicate2.5 MHz NVIS, Absorption?3.3 MHz NVIS4.6 MHz NVIS5.8 MHz 600 KM Skip7.6 MHz 1100 KM SkipE Layer Small

D LayerAbsorption

FoF1

F2

F2Multiple F2Reflections

Es Layer

Solar and Geomagnetic - Actual




Ionogram - Actual


E Layer

D LayerAbsorption

FoF2

MUF

Skip Distance

FoF2 / MUF Indicate2.5 MHz NVIS, Absorption Low?3.3 MHz NVIS, Absorption Low?4.6 MHz NVIS5.8 MHz NVIS7.6 MHz 900 KM SkipE Layer may cause Absorption

Es Layer

Ionogram - Actual

FoF2


MUF

FoF2 / MUF Indicate2.5 MHz NVIS, Absorption High?3.3 MHz NVIS, Absorption High?4.6 MHz NVIS, Absorption High?5.8 MHz NVIS7.6 MHz 500 KM SkipE Layer may cause AbsorptionE Layer

FoF2

F2

F2

D LayerAbsorption

Multiple F2Reflections

FxF2 Extraordinary

Es Layer

EsE

Austin not NE

Ionogram - Actual


Very FewF Layer

Reflections

Es Layer

D LayerAbsorption

Insufficient Datafor Digisondeto CalculateFoF2 and MUFE Layer may be blocking

FoF2?

MUF?

Skip Distance?

Es Layer

?

Ionogram - Actual


FoF2 / MUF Indicate2.5 MHz NVIS, Absorption High?3.3 MHz NVIS, Absorption High?4.6 MHz NVIS, Absorption High?5.8 MHz NVIS?, Short Skip, Long Skip, Some Attenuation7.6 MHz 500 KM Skip ?E Layer may cause Absorption and Short Skip

Es

EsD Layer

Absorption Multiple EsReflections

Es Layer

Es Layer

FoF2?

MUF?

Es

?

Skip Distance?

6 Meters Open?

Ionogram - Actual


FoF2 / MUF Indicate2.5 MHz NVIS, Absorption High?3.3 MHz NVIS, Absorption High?4.6 MHz NVIS, Absorption High?5.8 MHz 500 KM Skip, Short Skip, Some Attenuation7.6 MHz 1100 KM Skip ?E Layer may cause Absorption and Short Skip

Es

EsD Layer

Absorption Multiple EsReflections

Es Layer

Es Layer

FoF2

MUF

Es

Skip Distance?

Ionogram - Actual


FoF2

MUF

D LayerAbsorption

FoF2

E Layer

F2

F2Multiple

Reflections

FoF2 / MUF Indicate2.5 MHz NVIS, Absorption High?3.3 MHz NVIS, Absorption High?4.6 MHz NVIS5.8 MHz 600 SkipE Layer may cause Absorption

NVIS – Near Vertical Incident Skywave

Courtesy: Tom Carrigan / NE1R / AFA1IR

Typical NVIS RangeTypical Ground Wave Range

Ionospheric Layers

Resonant (Critical) frequency determined by electron density

http://dxc.wc2l.com/k1ttt/station/superstation_25/dvd_extras/k1ttt.net/technote/kn4lf/kn4lf8_files/ionosphereprofile.gif

Ionospheric Layers

Resonant (Critical) frequency determined by electron density

http://fas.org/man/dod-101/navy/docs/es310/propagat/IMG00024.GIF

Ionospheric Layers

http://www.electronics-radio.com/images/propagation-ionospheric-reflection-by-d-e-f-layers.svg

Ionospheric Layers

Ionospheric Layers

https://upload.wikimedia.org/wikipedia/commons/4/49/IonosphereLayers-NPS.gif

Ionospheric Layers

http://www.met.nps.edu/~psguest/EMEO_online/module3/rfig8.gif

Skywave Propagation

http://www.globalsecurity.org/intell/library/policy/army/fm/24-18/24180016.gif

NVIS when Skip Distance = 0, when F < FoF2

Sunspot Cycles


the ionogram and radio propagation · 2017-12-21 · the ionogram and radio propagation by terry g....

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