MAI75 - SSTV from International Space Station
Improving my ISS SSTV capture using my QFH antenna
SSTV on ISS
Russian cosmonauts on the International Space Station (ISS) transmitted Slow Scan TV images from ISS over 6/7 August 2021. More detail can be found here.
I slightly changed my SSTV setup as shown below. Mostly just using my QFH antenna over the Flower Pot.
|Home made QFH antenna
|Vertically mounted in a tree in the back garden
|5m of RG58 terminated in a BNC
|BNC to SMA adapter
|Connects the coax to my SDR
|This also does Satellite tracking and the Doppler correction
|Windows SSTV software
I've got this pretty well defined now. There are a number of steps that I followed:
- Identify a good satellite pass
- Set up the SDR (including audio recording for backup)
- Set up MMSSTV
- Capture signal during satellite pass
- Decode pictures in MMSSTV
So let's look at each step in turn.
Identify a good satellite pass
SDR Console lets me pick and track ISS. So I largely just identified when there would be a good pass and let it do its thing. In this case, I have 3 good passes on 6 August and 3 good passes on 7 August.
The second pass on the 6th was directly overhead (88 degrees maximum elevation), the lower passes were shorter but still good strong signals.
Set up the SDR
SDR Console has a great satellite plugin that knows all about ISS, its orbits and transponders. I just set up ISS in the scheduler and it handles tuning, including Doppler. All I have to do is turn on audio recording as a back up.
Of course, I have to remember to select the Virtual Audio Cable for output! You only forget that once.
Set up MMSSTV
MMSSTV is pretty much plug and play. I just fire it up, set it to the sync tab, make sure it is reading from the Virtual Audio Cable and that's it.
Capture signal during satellite pass
Not much to add here. The audio recording is a backup in case of software issues, but I haven't (touch wood) had any in this set of ISS passes.
Decode pictures in MMSSTV
MMSSTV largely just works, but I do have the option to replay the saved audio into it if there are problems in real time.
Conclusion and improvements for next time
Whilst I was able to obtain some good results, others in my club OARC were able to get even better shots with hand tracked Yagis. So I need to investigate a Yagi for next time...