Thursday, 26 January 2012

January update

January has been a busy month. Work and social commitments aside I have also dusted off the Nintendo Wii and am currently addicted to completing The Legend of Zelda - Skyward Sword. I am not an avid player of video games but really enjoyed Twilight Princess so treated myself to the game just before Christmas but hadn't had chance to play it. It is great fun, but sucks hours of your time without realising it.

Most of my radio monitoring this month has been done with my lovely FUNCube Dongle (FCD) which I have used for terrestrial signals as well as those from space. The ability to adjust the width of the demodulation makes it ideal for data decoding, got some very good VHF ACARS results and it is interesting to see the wonderful patterns the pagers, trunking and telemetry signals make on the waterfall display

I captured another ARISS contact from the ISS on January 18th on my traditional scanner but I haven't got around to editing and uploading the audio as it was conducted in Dutch.I have also done some further decoding of APRS packets from the ISS.

I have been getting to grips with the FCD's various idiosyncrasies and issues. The main one being it is very susceptible to overloading and image problems.One important lesson I have learned is turning down the front end LNA (Low Noise Amplifier) section actually helps to bring in those weak signals as they aren't lost in the mush!

That revelation came about while attempting to listen to some earth-moon-earth transmissions 'moon bounce' inspired by this posting on the Southgate Amateur Radio News website. Using the MAP65-IQ software and SDR-Radio I did manage to successful decode a handful of messages over the course of a few evenings but ironically it was from the loft mounted antenna using my main PC rather than from the hand-held directional YAGI. I suspect this was mainly because the laptop I was using outdoors was struggling to run both applications. The neighbours must have thought I nuts standing out in the garden in the dark, lit only by the security lights waving around a big antenna on a wooden pole - apparently pointing it at the full moon!

I have also had a go at receiving the VO52 - HAMSAT amateur radio satellite with the FCD this week as it currently has a decent morning and evening pass. This is an interesting satellite as the transmissions are SSB rather than FM and during the pass the waterfall display is awash with lots of overlapping transmissions all shifting frequency with what sounded like lots of 'whistling'

You can get a idea of what it sounds like from these videos

To be honest I was a bit confused by what I receiving until I saw these videos. What I believe is happening is the operators are trying to correct for the doppler and overshooting or undershooting. I will be making some videos myself once I have mastered the art of chasing the signal!

No comments: