Radio-to-Soundcard interface to receive satellite SSTV

The ARISSat-1/KEDR team have released this information about receiving the satellite:

The FM downlink on 145.950 MHz will be audible on all common 2 meter amateur radio receivers with no modification needed to your equipment.

A CW/SSB receiver will also receive the CW beacons on 145.919 MHz or 145.939 MHz and the signals on the linear transponder passband between 145.922 to 145.938 MHz.

To take advantage of the full bandwidth of the downlink for SSTV, CW Decoding, BPSK Decoding you’ll need to add a few things:

+ You’ll need an audio patch cable from your receiver to your computer soundcard audio input. If you are already on the air with other amateur radio soundcard applications then you are ready with the hardware to receive, decode, and display the SSTV, BPSK-1000 or BPSK-400 downlinks.

+ You’ll need SSTV software (refer to the SSTV news item)

+ You’ll need the ARISSatTLM software to decode the BPSK telemetry. (refer to the ARISSatTLM news item)

The key difference is that the SSTV signal is transmitted on the
FM downlink on 145.950 MHz. The BPSK-1000 downlink is transmitted in SSB mode on 145.920 MHz. Depending on your equipment you may need to fabricate an audio patch to the computer soundcard input from both your 2 meter FM radio and 2 meter SSB radio.

An initial “RECEIVE ONLY” configuration is easily done consisting of an audio patch cable between your radio and the soundcard. The ARISSat-1/KEDR team testing the software noted that a minimal set up consisting of an audio cable from the speaker or headphone output from the radio to the line (or mic) input on your PC sound card was successful. If your rig has a ‘Line Out’ audio connection this can be run to the soundcard ‘Line In’ connection.

Many amateur radio “digital modes” articles, web pages, and books also discuss the more complex requirements to interface your transmitter to the soundcard and to control the push-to-talk functions. This is NOT required for you to successfully receive, decode, and display the signals you receive from ARISSat-1/ KEDR. To join into the all the fun your “RECEIVE ONLY” configuration will just need the audio cable!