Monthly Archives: January 2016

QFH Antenna and my first reception of NOAA!


So in my last post I was playing with my RTL-SDR with an Intel Edison. So I decided to build a QFH Antenna to ble able to receive NOAA APT Signals. These NOAA Weather Satellites broadcast a APT signal with about 5 to 8 Watts at 2m band, and considering how low this power is, it might suprise you that these signals arrive pretty strong at earth surface. But the biggest challenge to receive this signals are not its power. Its all about movement.

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Play with SDR and Intel Edison!

So some people already saw in my facebook that I started playing with SDRs (Software Defined Radio).

I always wanted to do my own radio receiver, and I did some in the past. But it’s very hard to adapt the radio for anything new you want do to, and also when you want to process data in your computer things become harder.

So a few months ago I found a nice tutorial of how to get NOAA Satellite Images using a cheap DVB-T (Digital Video Broadcast – Terrestrial) dongle that can be used as SDR. It costs about R$70 (roughly US$10) and the model I got (with R820T2 tuner) can tune from 24MHz to 1.74GHz!!!

What is inside this spectrum?

Actually a lot:

  • FM Audio Radio Broadcasts
  • VHF / UHF Television (Both Digital and Analog)
  • Weather Satellites (APT, LRPT, HRPT)
  • ADB-S (Air Traffic Telemetry)
  • FM Air Traffic Radio
  • And more

So my goal was to receive NOAA APT Signals (I even made a decoder!) but I don’t have a good enough antenna (yet).

The problem

So I made up a piece of antenna with two copper pipes (I call a piece, because its a dipole from a Double Cross Antenna) (I will make a tutorial later how to do it) to have better reception for the 2m band (~135Mhz) but every time a satellite was in range, I would need to go outdoor and turn on my laptop and start capturing. This was annoying.

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