Updated March 2021
Weather Satellites transmit High Resolution Pictures (HRPT) at 1.7 GHz. The transmission is not encrypted and all needed is a low noise antenna and LNA , an SDR and suitable software for demodulation, decoding and visualization.
The minimal, portable setup regularly in use here is an Airspy Mini USB SDR , a 40cm diameter helicone on a tripod tracking sats by hand and a 0.2 dB NF LNA.
SDR Airspy Mini and USRP1 (modified clock 48 MHz, streaming 6 MSPS)
Antenna and Tracking :
a) Hand tracking using a small low noise helicone antenna (see dimensions below)
b) Automated tracking is done using my own Satellite FUN software and a SPID BIG RAS rotator.
Low Noise Amplifier:
Modified G4DDK VLNA NF 0.2dB – absolutely important when the low noise helicone antenna is used.
For demodulation and decoding one could use one of the following:
a) Aang254’s excellent free SatDump which supports VHF/ L//S/ X band weather satellites and much more : https://github.com/altillimity/SatDump !!!
For visualization / false color images :
a) David Taylor’s HRPT reader and
b) Fred Jansen’s weathersat
Some pictures showing this small portable setup and what it can do , can be found below.
1.7 GHz helicone design:
The helicone antenna below has been simulated and optimized in CST Microwave Studio.
The goal was minimum dimensions for acceptable G/T performance.
If you decide to build this antenna, it is absolutely important to use a very low noise amplifier (0.2 -0.3 dB) like G4DDK’s excellent VLNA.
Performance will be very poor with the popular 1-1.5 dB Noise Figure LNAs…