One of the many experiments aboard the ISS is an amateur radio transmitter. It is regularly used to transmit images to Earth, using a fax-like mechanism. A tranmission was held on Wednesday 1 December 2021.
To receive the images, only a relatively small antenna is required; a ‘walkie-talkie’ at 145.800 MHz suffices. If you don’t have that, you can also use the antenna next to the Dwingeloo telescope. The signal of that antenna is streamed to our website. This website converts the signal into sound. To convert that sound into an image, you need a computer program or an app.
Our favorite way to set up this experiment is not optimal, but quite easy. You need a computer and a mobile phone:
- On the computer, go to our WebSDR and tune to 145.800 MHz FM (this will happen automatically if you follow this link).
- On your mobile phone, install the free app Robot36 (Android) or SSTV Slow Scan TV (iOS). This app listens to sound, and converts it to images.
You can test the app by playing a test recording on the computer and listening to it with the app (if necessary, set the app to mode PD120). The test recording was created by us, it was not sent by the ISS.
This was the short explanation; last year, ESA made an extensive set of videos to explain this process step by step. Below the ESA video is a list with instructions for other platforms, e.g. Windows and MacOS.
This experiment only works if the ISS is transmitting, and if the ISS is below the horizon. The ISS is moving at a speed of about 7.6 km/s, so it is above the horizon only a short time. The times below are exact!
- Monday 27 December: 03:35 – 03:45 UTC
- Monday 27 December: 05:11 – 05:22 UTC
- Monday 27 December: 06:47 – 06:58 UTC
- Monday 27 December: 08:24 – 08:35 UTC
- Tuesday 28 December: 02:47 – 02:57 UTC
- Tuesday 28 December: 04:23 – 04:34 UTC
- Tuesday 28 December: 05:59 – 06:10 UTC
- Tuesday 28 December: 07:36 – 07:47 UTC
- Wednesday 29 December: 03:35 – 03:46 UTC
- Wednesday 29 December: 05:11 – 05:22 UTC
- Wednesday 29 December: 06:48 – 06:59 UTC
- Wednesday 29 December: 08:25 – 08:35 UTC
- Thursday 30 December: 02:47 – 02:58 UTC
- Thursday 30 December: 04:23 – 04:34 UTC
- Thursday 30 December: 06:00 – 06:11 UTC
- Thursday 30 December: 07:36 – 07:47 UTC
- Friday 31 December: 01:59 – 02:10 UTC
- Friday 31 December: 03:35 – 03:46 UTC
- Friday 31 December: 05:12 – 05:23 UTC
- Friday 31 December: 06:48 – 06:59 UTC
Note that this is an experiment, so your mileage may vary. This can be due to the app’s settings, or problems with our reception. If you do manage to get a nice image, we’d like to hear from you. Let us know over one of our social channels.
You can also submit the image to the organization behind the experiment: ARISS.