Monday, 10 September 2012

Software Defined Radio hacks

The radio meteor project was great but has a few hang ups that are bugging me...

  1. The hand-held yupiteru radio has some issues with frequency stability that makes it difficult to work out what's a satellite and what's a glitch in the radio.
  2. The radio/soundcard interface seems to be susceptible to RF interference - eg from my computer monitor! This creates noise and false alarms on the meteor counter
  3. To detect meteors, my PC must be on and running the speclab software with the radio attached. This is tedious and uneconomical to run 24/7
  4. The feedline from the aerial to the radio is about 15m long. This may cause line losses (ie the signal gets weaker)
So to fix these I'm planning on using a digital tv USB dongle and an arduino to create a detector-in-a-box that could run off a low-wattage wall-wart and could dump data onto a USB stick or live stream over wired or wireless network onto the internet...

Fun, eh?

The system relies on a modern miracle chip built into some brands of USB digital TV dongles. The realtek Software Defined Radio (SDR) lets you tune into a huge range of frequencies (around 70MHz to 1.7 GHz). I got a generic one from Amazon for £17. There are a few sites around that list compatible dongles.

More to come on HDSDR and how to grab the data coming off the dongle...

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