Talking Satellites

Last edit 26.sept.2019

I thought about putting together some helpful information for working on satellites, a very beautiful and challenging area, where the efforts are fully rewarded.

There are many satellites for amateur radio traffic, either digital or voice repeaters, or that send weather maps with the earth from space. Astronauts from the International Space Station sporadically establish links with radio amateurs and interview students from schools. You can receive all these transmissions, plus there are SSTVs with anniversary occasions, communications between EVA participants and other stuff that occur all the time.

Most of the connections are in the VHF / UHF, are made with low power (4-5W are sufficient) and last very little, maximum 10-15 minutes, because this is what it takes the satellite to pass over your head. It’s not like the ground connections, where you have enough time, so the preparation beforehand is very important.

For mobile devices, this widget looks better in LANDSCAPE

First of all, the transceiver must be connected to the audio interface of a computer. Received audio signal go to LineIn-soundcard and Speaker-soundcard must reach the station’s microphone – for transmission. All solutions are already described on the net. Some stations have a dedicated connector for this. It resembles the PS2 computer jack.
Image result for ham radio data connector

There’s still the PTT problem. If the radio has VOX, you’re good. If not, you need to do a VOX circuit. Like here.

ISS – PACKET/APRS = 145,825 MHz
– SSTV = 145,8 MHz / PD-120 mode
– VOICE = you receive on 145,8 MHz /transmit on 145,2 MHz
– VOICE Russian = 143,625 MHz

PSAT (No-84)– PACKET/APRS =145,825 MHz, PSK31 FM = 435.350 MHz
PCSAT (No-44)
– PACKET/APRS=145,825 MHz
NOAA15 – 137,620 MHz / bandwidth 30KHz
NOAA18 – 137,9125 MHz / bandwidth 30KHz
NOAA19 – 137,100 MHz / bandwidth 30KHz

SOFTWARE very necessary. All free.
Orbitron – Satellite Tracking System. With a huge database, you can track the orbit of hundreds of satellites and make predictions when they pass over you.
MixW – Multimode software for radio amateurs. Make digital connections via ISS or other satellites. Decode a lot of digital modes, you can periodically broadcast for APRS, make logs …
SDR# – SDR software (software defined radio). Find a lot of plugins for all kinds of decoding – directly or through the sound card.

MMSSTV – Slow Scan TV with Windows and Soundcard. For sending / receiving images. Many modes, automatic recognition, templates.
WXTOIMG – The world’s best weather satellite (WXsat) image decoder. Decodes weather images transmitted by NOAA satellites with the Earth’s globe from space.

FOR MOBILE DEVICES – still free.
Cover art
ISS Detector – See the Space Station. Track the Space Station, make predictions, set alerts.


Cover artHeavens Above – Track a lot of satellites and make predictions when they will come across, find satellite information as up/down frequencies, see what’s above right now.


Cover artAPRSdroid – is an Android APRS reporting tool. Send and receive APRS with your mobile phone and a portable radio station, connected with an audio cable.
Here you will find one of the many connection examples, with explanations for setting up the station and the phone.

SITES of great help to prepare, work and see what you have done. – The Radio Amateur Satellite Corporation – almost all satellites on which radio amateur traffic can be made. STATUS, SOFTWARE, FREQUENCIES – a site dedicated to links through the Space Station repeater. See who sent and if you were heard. – schedule of SSTV transmissions on ISS – about voice transmissions / interviews with ISS astronauts – a large database with CALLSIGNs and various news. – positions map (APRS) transmitted by citizens and received and put on the net by various servers. Also to see if anyone received you. – map with the positions of transmissions and receptions worldwide, in all bands. – satellites
tracker, orbits, predictions, information and space news.

ANTENNA. I think, the most important element.
Related image
I did this (left image) and it works great.
Here is a very good site.
And here there are other antennas, good for inspiration.


work in progress…
Any suggestion is welcome.