More satellite tracking software de DK1TB Satellites for SWLs - using a loft-mounted vertical folded dipole for the 144-146MHz band and a 2m FM/USB/CW RX is sufficient for me to discern satellites.

Check out for homebrew 2m aerial & below interface & free software to predict satellite passes.

I use a 1:1 600 Ohm audio isolating transformer -20dB interface from Line Out or Headphone socket of receiver then a resistor pad as required e.g. two resistors 47k Ohm each in series and parallel after the transformer then 2·2uF DC Blocking Capacitor for connection to Lap Top or PC. Source: eBay about £10. Thank you to Norman G8ATO of Verulam ARC for technical advice.

I use SatExe from Gabriel RIVAT F6DQM  It requires a Keplerian data file to predict the satellite passes. My machine will not accept .all files so I visit:   then I right click on the web page then save it as nasa.txt file then copy it into the SatExe folder. Alternativley visit: then right click over the web page and save the amateur.txt file then copy it into the required folder. Once a week is usually sufficient except ISS which may drift frequently. Alternatively Google: 'Heavens Above' and print off daily predictions. * = sats heard.

Download freeware WYSIWYH - What You See Is What You Hear (a WAV audio file recorder) to save those precious few moments of satellite passing, for analysis at leisure, also from the web site of Gabriel RIVAT F6DQM above. Donations appreciated for his work. The Doppler effect may cause satellite USB/FM Downlink frequencies below to ± 2·5kHz.

*AO-07 Downlink: 145·925 MHz - 145·975 MHz - batteries failed so sunlight only
*AO-73 Downlink: 145·950 MHz - 145·970 MHz BPSK 145·935 MHz - FUNcube-1
*AO-85 Downlink: 145·980 MHz - Fox-1A
 EO-79 Downlink: 145·935 MHz - 145·965 MHz USB FUNcube-3 sunlight only
*ISS   Downlink: 145·800 MHz - VHF Packet: 145·825 MHz & UHF Packet: 437·550 MHz CW ID RS0ISS
*XW-2F Downlink: 145·980 MHz - 146·000 MHz - CAS-3F
*LilacSat-2 Downlink: 437·222 MHz Machine Code - CAS-3H
 UO-11 Downlink: 145·825 MHz - Beacon only rarely heard.

70cm GP Those with UHF 70cm may consider ¼ wave ground plane antenna hoisted to the apex of the roof in the loft. Illustration sourced from the Internet and my dimensions added.

*FO-29 Downlink: 435·900 MHz USB 435.840MHz CW
*SO-50 Downlink: 436·795 MHz - FM ± 10 kHz Doppler SaudiSat 1-C
Kenwood TS-2000 has a 'birdie' on SO-50 frequency. YMMV. Calibrate your PC clock. Unlike most states in Europe, Iceland Summer (Daylight-Saving) time is not observed. Therefore set hobby radio PC clock to 'Reykjavik' GMT/UTC/Zulu time to ensure year round conformity of e.g. your logging program. Also applies to Monrovia in Liberia. AMSAT sats status  DK3WN sats status If you are in the UK, you can listen to radio signals from the ISS when it's in range via the Southampton University Wireless Society WebSDR. If you're to the East of the UK, you can listen to the ISS when it's over Russia on the R4UAB WebSDR Source: Radio User magazine October 2016. In loving memory of Harry G3FHU & Des G3PTV. Updated: 28th August 2016 73 Bob G4PVB MA3053SWL

p.s. The EO-79/FUNcube-3 satellite has transitioned to amateur radio service, now that its primary mission has been completed. AMSAT-UK and AMSAT-NL have announced that the FUNcube U/V transponder has been activated with a regular schedule. Due to power budget constraints, the transponder cannot operate 24/7, so an orbit-specific schedule has been developed. The transponder will commence operation 27 minutes after the spacecraft enters sunlight and remain active for 25 minutes. This schedule may be modified in the weeks ahead, as experience dictates. The transponder uplink is 435·047 to 435·077MHz LSB; the downlink is 145·935 to 145·965MHz USB. The output power of the amateur radio payload is about 400mW. Source: RSGB 19 November 2016.

p.p.s. Practical Wireless January 2017 reports that ISS VHF equipment broken down so now temporarily using Russian radio for packet allowing for Doppler Shift on:

Channel  RX(MHz)  TX(MHz)
1       *437·560  437·540
2        437·555  437·545
3        437·550  437·550
4        437·545  437·555
5        437·540  437·560

Tim Kirby G4VXE of Practical Wireless magazine: "Dear Bob, Glad you heard the ISS ok. Have you tried listening for the ISS 143·625MHz downlink? Not amateur traffic but the crew talking to Star City in Moscow. You might find it interesting. Vy 73, Tim"

Often when setting up a VHF scanner RX and/or aerial you really do want a reliable continuous 24/7 broadcast to help monitor your progress. I use the continuous aeronautical weather TXs e.g. London Main information broadcast 135·383 MHz AM. YMMV with: London Volmet (Main) 135·375MHz, London Volmet (South) 128·600MHz, London Volmet (North) 126·600MHz, Scottish Volmet 125·725MHz. Source: where the information codes are explained in detail.


New FM repeater satellite RSGB | November 24, 2017
A new easy-to-use amateur radio satellite was launched last weekend and was switched on for general use on Thursday. AO-91, also known as RadFxSat and Fox-1B is a Cubesat that carries an FM transponder.

The uplink is on 435·250MHz FM, plus or minus Doppler, with a mandatory 67Hz CTCSS tone for access.

The downlink is on 145·960MHz FM.

The present position of the satellite can be seen at and all amateurs are invited to listen out for the bird.

The northernmost point of its orbit periodically passes roughly over Bedford, meaning that it will give good service over the whole of the British Isles, Europe, and beyond.

Full details about the satellite are on the AMSAT-UK website.

By coincidence, another AMSAT mission, FUNcube-1, also known as AO-73, celebrated its fourth birthday in space this week. It has travelled well over 500 million miles in orbit since launch and been received tens of thousands of times.

I received this ISS Russian sector SSTV picture 06th December 2017. 145·800MHz FM. Doppler effect requires continual RIT as the bird passes overhead. During the 'space race' the Americans developed, at significant cost, a pen that could work in zero gravity. The Russians responded by using a pencil...

SSTV Frequencies MHz

3·845 (LSB) 3·730 Europe
7·171 (LSB) 7·043 Europe
14·230 (USB)
21·340 (USB)
28·680 (USB)
144·500 (FM)
145·800 (FM) ISS

ISS Frequencies source: ISS Fan Club
Amateur Radio MHz Frequencies (Note: Only one mode active at a time) FM VOICE for ITU Region 1: Europe - Middle East - Africa - North Asia

Downlink 145·800
Uplink 145·200

FM VOICE for ITU Region 2&3: North and South America - Caribbean - Greenland - Australia - South Asia

Downlink 145·800
Uplink 144·490

FM U/v VOICE Repeater (Worldwide)

Downlink 145·800
Uplink 437·800

FM V/u with PL VOICE Repeater (Worldwide)

Downlink 437·800
Uplink 145·990 with 67.0 PL

FM L/v VOICE Repeater (Worldwide)

Downlink 145·800
Uplink 1269·650

AX.25 1200 Bd AFSK Packet Radio (Worldwide)

Downlink 145·825
Uplink 145·825

FM SSTV downlink (Worldwide)

Downlink 145·800

UHF Simplex (rarely used)

Downlink 437·550
Uplink 437·550

Other Frequencies

121·125 FM
RS EVA from Orlan suit[Credit N5VHO]
121·700 FM / 121·750 FM
Downlink from Soyuz-TM (voice). RS EVA from Orlan suit. Soyuz VHF-2. Progress Telemetry. [Credit N5VHO]
130·167 FM
VHF-2 Downlink from Zarya (Service Module). RS EVA to Orlan suits [Credit N5VHO]
143·625 FM
VHF-1 downlink. Main Russian communications channel. Often active over Moskow. You can hear air to ground conversations in Russian. Sometimes English when US crews talk to their NASA representative in Star City. [Credit IZ6BYY]

Return of Experimenter's Wednesday to AO-85
With the recent popularity of Slow Scan Television (SSTV) from the ISS, AMSAT Operations is bringing back Experimenter's Wednesday to AO-85

On a trial basis, we invite users to exchange pictures using Robot 36 SSTV mode via the FM repeater on AO-85 during UTC Wednesdays. Please identify prior to beginning transmissions, and only send when the uplink is clear.

Stations are requested to only uplink if they have a reasonable expectation of maintaining a full-quieting signal for the duration of the image transmission.

Smaller stations are encouraged to focus on receiving the images.

Please don't send questionable or provocative images. If in doubt, pick another one. Expect all ages to be participating.

Feedback is encouraged, and comments may be directed via email to me at ko4ma at amsat dot org.

Drew KO4MA


Weather Satellites: 137 - 138 MHz. The polar orbiting satellites transmit on 137.10, 137.30, 137.40, 137.50, 137.62, 137.80, 137.85 or 137.9125 FM (50kHz or NFM) and each satellite will pass by twice per day (about 12 hours apart) at roughly the same times each day. Source: WXtoimg - software to decode weather satellite images: TLE Data from

As at 07th January 2018 there are only three NOAA (National Oceanic Atmospheric Administration) weather satellites fully operational:
NOAA 15 137.620MHz
NOAA 18 137.9125MHz
NOAA 19 137.100MHz

Satellite information is constantly changing. The update below is at 08th May 2018.

SATID Downlin Up-link Tone

SO50E 436.802 145.847 88.5
SO501 436.802 145.847 67.0
SO502 436.794 145.850 67.0
SO503 436.786 145.853 67.0

AO851 145.980 435.180 67.0
AO852 145.977 435.172 67.0
AO853 145.974 435.164 67.0

AO911 145.964 435.242 67.0
AO912 145.961 435.250 67.0
AO913 145.858 435.258 67.0

AO921 145.883 435.342 67.0
AO922 145.880 435.350 67.0
AO923 145.877 435.358 67.0

VHF 1 is 143.625 MHz (the standard Russian ISS downlink frequency) and
VHF 2 is 130.165 MHz (the Soyuz downlink frequency).
My satellite favourites as at 15th June 2018

I received ISS SSTV PD120 image above 30 June 2017. I used folded dipole in the loft (see 1st link below) a 2m FM receiver and RX-SSTV software. To predict the satellite pass I used SatPC32. The Doppler effect required me to continuously tune from 3kHz high as ISS approached, 145.800MHz when directly above, then down to 3kHz low as it passed me by. The SSTV transmission is interrupted by approximately a minute so it is easy to miss the signal as the satellite passes. SatPC32 will give you guidance on the current downlink frequency. You can see from the 'noise' on my image that I was continuously tuning and retuning to maintain a good signal. This is an ideal exciting SWL project. The aerial can be made from DIY store components, the softwares are free and you could use a basic FM handie (employ a flexible pigtail lead to protect aerial connection) with possibly incremental tuning frequencies stored in the memory. My radio did not have a Line Out so I used the headphone socket with interface via 2nd link below. In order to hear the signal I fed the PC audio out to the input of an old radio cassette recorder that would also give me the option to tape the signal for future experimentation.

143·625 MHz FM? ISS to Star City Moscow
121·125 MHz FM ISS spacewalks
121·750 MHz FM ISS spacewalks
145·800 MHz FM & SSTV

SWL orientated ISS RX-SSTV:

I'm delighted to tell you that today 27 Oct 2018 and subsequently 28 Oct 2018 morning & afternoon I copied the ISS SSTV using just an aerial in the loft and a 2m receiver set at 145·800 MHz USB. useful to determine when to listen or try SatPC32 free basic software. Although the attached pictures may look a bit 'art school' it does illustrate how I had to continually retune my radio to account for Doppler shift typically ± 2·5 kHz. I used headphone out from my radio through an isolating 1:1 600 Ohm transformer into the audio of my PC but you could likely go direct if you're careful with the levels. RX-SSTV de Guy, ON6MU free SWL orientated slow scan TV software (link below) that automatically selects PD120 mode for ISS but you can select manually if needed. When you hear the signal it sounds like a continuous high pitched chug a chug of an old steam traction engine. At the end of an image there is a pause in transmission where you must anticipate (continuous retuning likely needed so don't just wait in one place or you'll miss out) where the signal has moved to before the next image. Thank you to Norman G8ATO of Verulam ARC for technical advice.

Visit links below for ISS SSTV schedule of transmission updates. You'll likely get ten days notice of Russian / NASA sector images:

ARISS - Amateur Radio on the International Space Station