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Sunday, February 17, 2019

SSTV from SPAAAAACE! International Space Station Sends Images


The crew on the space station have been transmitting SSTV images.   This morning I threw together a receiving system:  I used my four element refrigerator tubing quad feeding the an RTL-SDR Dongle with HD-SDR software in the computer.  For the SSTV decoding I downloaded a program from Japan: MMSSTV (very nice).  To get the signal from HD-SDRto MMSSTV I just plugged a cheap little electret computer mic into the computer and taped it to the speaker.  

At 0838 local today ISS flew almost directly over me.   I aimed the quad south-west, and almost as soon as it was above the horizon very strong signals started pouring in.  They produced the first picture (above).  

ISS went silent as it passed over head. I swung the quad to the north-east hoping to catch another image as the station moved away.  That is the second image (below). You can see that I was losing the signal about halfway through.  

The distortion in the video image may be the result of me manually adjusting the receiver for Doppler shift. 


Here is a little video of the action in the shack during the first half of the pass. 


Here is the RTL-SDR Dongle Receiver in an Altoids Box: 

Here is that the programs looked like on the screen -- HDSDR on top, MMSS on the bottom:  


Here is what the orbital pass looked like. ISS was East of New Zealand when I took this picture.  ISS came up over the Eastern Pacific and Mexico before passing over N2CQR.  This display comes from the excellent Heavens Above web site:  




1 comment:

  1. Nice attempt Bill. In your pictures MMSSTV is trying to correct timing errors in the SSTV signal that are caused by the doppler effect on the ISS signal. MMSSTV thinks it has to re-synchronise the signal every few lines. Try going to "Option", "Setup MMSSTV", "RX" and enable "Auto Slant" and maybe disable "Auto Resync". That should result in better images from ISS.

    Have fun!

    JOHN, M5AML

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