Nice SSTV Image from Space Station!

It is a long time since I had tried receiving an SSTV (Slow Scan Television) image from the International Space Station. For the past few days, my X profile was being flooded with SSTV images from Space Station. The event is from 11th to 16th April 2025 and the transmission is on 145.800 MHz. Anyone with a VHF radio and a mobile phone can receive and decode the images. You don’t even need an amateur radio license to receive an image as you are not transmitting anything. I used my IC 2730 dual band base station, though a handheld radio should be enough. Though I have not tried it out, the small Software Defined Radios like RTL-SDR which covers the VHF band should also be sufficient. Robot36 app is installed from Play Store in your mobile phone and kept running while the radio receives the signals from the space station. Images are transmitted intermittently for 2 minutes, with a gap of 2 minutes.

Pass direction and timing can be obtained from N2YO.COM and has been shown here. Best reception will be at the time of closest approach when the satellite is nearer to you. High elevation passes will be best for low setups like a hand held radio. If there is a directional Yagi antenna which can be rotated in azimuth and elevation along the pass direction and elevation, even low elevation passes can be used. This one was a pass with maximum 21 degree elevation in my region and I got one image well. An earlier image was not received fully.

I had used my CP22E VHF omnidirectional antenna for reception. The antenna was mounted at about 7m from the ground. If Doppler correction is done for the movement of the satellite, with slightly higher frequency at the beginning of the 10 minute pass and slightly lower frequency towards the end of the pass, more images can be obtained, in a better quality. I had not used Doppler correction as I had the intention to get only one image at the time of closest approach. Doppler correction can be done either by switching frequencies at 2.5-5 kHz stored in the memory or manually if you are operating indoors from a base station.

I have recorded the audio from the SSTV transmission in another phone and you can hear it at the end of this video. If you want to try decoding, go ahead and install Robot36 app in your phone and keep this audio near your phone with the app open. Then you will get the thrill of SSTV decoding even without a radio and antenna. After that you can try decoding with your radio as the SSTV event is likely to be there upto 16th April 2025, commemorating anniversary of human space flight. As the transmission are at high power of about 25W, even those with limited setup can decode it if you listen at the right time given at N2YO.COM.

Here is the image which I decoded again from the recorded audio. Much better images can be decoded if you use directional antennas, especially during high elevation passes, with automatic Doppler correction and antenna rotation using software for satellite operations like Gpredict.