SSTV from the ISS - ARISS 20th Anniversary - July 2017
ARISS celebrates its 20th Anniversary with a SSTV event from the International Space Station. he ISS is sending SSTV images from the 20.07.2017 (~21:25 UTC) until the 24.07.2017 (~18:00 UTC) on 145.800mhz. This time they are using the PD120 protocol, so each image only takes 2 instead of 3 minutes.
Like many others around the World, I will try to get as many images from the ISS as possible during the weekend. Unfortunately all passes of the ISS are in the middle of the night for me (and anyone around Germany) what is not that great. As the day go by, i will update this blog ost with my received images and what else was happening around it.
Setup and First PASS
Because I had to Work on Friday, I was not able to walk around the Field all night. Because of that my Plan was to set up my SDR and auto record the Images with an Antenna on the roof. I Used my Notebook, a SDR v3 dongle, an LNA4ALL, an FM Trap and an V-dipole Antenna. The Antenna is a design from ADAM (9A4QV) that also sells the LNA4ALL. I made a 3d printed part that ensures that the Antenna has a angle of exactly 120° from leg to leg. After setting everything up it was already time for the First pass of the ISS, so I wanted to ensure that everything works and then go to bed and let it auto record.
The pass (~0:29 MESZ) was really bad with a predicted max elv. of only 14° and duration of around 40s. To my surprise I got a SSTV Signal 3 or 4 minutes before it was predicted and even on that low pass I got parts of a picture. Would I have pressed Record earlier I would have gotten much more of the first image.
My Notebook died....
...30s after the automatic recording stopped. I got a bluescreen and it was not starting anymore. After letting it sit for an hour, it started up but then crashed again after some minutes and before the next ISS pass :( It seems that the CPU/GPU (APU) of the Notebook is the problem, so I will not be able to receive anything on the go with my Yagi I think. But i will setup something else for the V-dipole.
Second Night - Success!
Instead of my Notebook is used my GPU Miner to run SDR# and RX SSTV. I first thought about Mining and recording at the same time, but the GPUs where causing issues on my flight radar so it could interfere with the ISS signal as well. Because of that, I disconnected all GPUs except one. I also waterproofed my SDR, FM Trap and Booster with some tape, because they had to stay outside in the predicted Rain. The First pass had a max elv. of only 22° but i still got the following little part of an image:
In the next two passes that where around 75° max elv. I got two full pictures:
The last pass that night had a max elv. of 56° and i was able to get almost a full image:
Third Night - Thunderstorm...
The first pass was only 14° so I tried to receive an image with my Yagi and Baofeng while standing in the open field. Unfortunately the ISS had a 6-8 minute gap between the transmission instead of only 2 minutes. Because of that, the Signal begun at the end of the pass from around 10° elevation. I only used a little DVR to record the audio with the internal mic but I still got a part of image 10/12:
As my bad luck continuous there was a thunderstorm during the second pass (56° max elv.), so I had to get the Antenna (incl. SDR,Booster etc.) inside the house to close the window. Without any expectations I tried to receive the ISS from inside the House with my DIY Yagi and Baofeng. "That will never work, all these houses out of concrete and stone will block the signal." ... I was thinking.
Surprise! I got a Signal! A very strong Signal! but I was still using the DVR mic....so the image is not that nice but a part of 8/12:
The next pass had a max elevation of 75° but my V-dipole on the SDR had a short from the Thunderstorm and the hectic break down. But I also tried to receive something with my Yagi from inside the house as before. This time I used my windows Tablet and an USB sound card to record the audio. If my tracking have been better, I would have received an almost perfect image 7/12:
After repairing my V-dipole I got a great image 6/12 on the SDR, and a part of it with my Yagi (again indoors):
The last passes of the Event for me are 38°, 82°, 88° and 32°. But I think i will not be able to get much because I can only use auto record.
Server noise and windows freezes
As my bad luck continues, my Miner freezed as many times before at the weekend and nothing was recorded in the night. Also my Tablet turned on without me noticing it, so the battery was empty when I wanted to set it up for recording my Baofeng on the same V-dipole as the SDR. Because of that, my only option was to use the DVR to record the sound of the Baofeng speaker. This time I did set the volume not as high as before to prevent overloading the DVRs microphone. Unfortunately the DVR decided to record more of the Fan Noise of my Server, then the SSTV signal from the Baofeng. I was able to decode something that would have been image 12/12....
Results
Even with all that Bad luck, technical dificulties, the stupid time of the ISS passes and the timing of transmitting (6 minute pass: 2 min gap - full image - 2 min gap) I got the following Result.
- 3 Full images (4/12, 5/12, 6/12)
- 2 almost Full images (2/12, 7/12)
- one almost Full but noisy image (8/12)
- one half image (10/12)
- a very noisy part of an image (1/12)
I also got some little part's of images.
One of the main Issues was that my Notebook died after the second pass of the Event. I even replaced the APU (CPU/GPU) on the weekend and hoped it will fix the GPU Issue I got bluescreens for. But no, the second GPU that is not replaceable is dead, that is also not deactivatable. The next Problems where the unstable replacement PC (aka. Miner), the crap microphone recording of the DVR and the shorting of my v-Dipole because of a loose connection (I hate Choc blocks, but soldering to aluminum is not possible :( ) what gave me two lost SDR recordings.
I'm already looking forward to the next ISS SSTV Event that hopefully is still this year.
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