APRS with the International Space Station (ISS)

An evolving notes-to-self type post…

The ISS has two digipeaters. One on 145.825 MHz and another on 437.550 MHz. The 2m being easier to use, as you don’t really need to account for doppler is the most popular. Though the 70cm was in widespread use when the 2m went offline a couple of years back.

Advised setup seems to be to use UISS and AGWpacketengine (AGWpe).

For listening I’m going to the use the FCD+ taking an audio feed to the virtual audio cable and then have the other tools have at it. I expect I could just use MULTIPSK here but hay let’s install more radio tools…


Start AGWpe first. You need to set up the Radio Port. Mine looks like:

When you select soundcard you can select the device that it uses:

With that done we can open UISS and it will use that Port:


Open SDR# with the FCD+ with a 2m antenna and the output going to the virtual audio cable (windows direct sound ). Go to 144.800MHz WFM. You should then start picking up aprs messages:


Since there’s no waterfall on UISS or AGWpe I used multipsk to ensure that basic reception was working. Set the input to be the virtual cable and the decode to be Packet+APRS. You should see the signal on the waterfall corresponding to the waterfall on SDR# and see a decode. If this doesn’t work UISS/AGWpe won’t either.

Next Steps

The ISS is broadcasting SSTV at the moment but according to http://www.ariss.net/ there are packets being recorded. So I’m going to record the baseband of the overnight ISS passes to decode the SSTV and hopefully get some APRS packets to look at as well.

An Aside

There are some interesting stations cropping up on my APRS test monitoring. I’ll have to try and work through some of these at some point:

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