Wednesday, 26 June 2013

ISS - Russian EVA-33 Comms received using RTL-SDR

Back in April I managed to receive some of the communications downlink from the Russian section of the International Space Station during a EVA/Spacewalk using a FUNCube Dongle Pro+ connected to my discone.

On Monday this week I was alerted to another ambitious EVA being performed by Cosmonauts Fyodor Yurchikhin and debut spacewalker Alexander Misurkin. Details of the EVA can be found here.

The EVA lasted over six hours on the outside of the ISS. The duo conducted a large array of tasks, including the replacement of a fluid flow regulator on the Russian segment’s Zarya module.

As luck would have it the EVA was in progress during several passes over the UK. Unfortunately as I was unaware of it at the time I hadn't prepared and was stuck in work. I can remotely access my computers and the only receiver I had available was an RTL-SDR which was connected to a random HF long-wire antenna in the loft!

Undeterred I set it recording using SDR# and was surprised at the quality and strength of the signal during the first two passes, so much so I left it connected for the third pass in the evening, again the downlink signal was on 143.625MHz, with the obvious doppler shift.   

I have played back the recorded IQ files and made a video using CamStudio to record directly off the computer screen, the audio and video go out of sync and the frame rate isn't brilliant.

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