Since last week's video on this satellite got a lot of interest, here's a follow-up! I wanted to address the most common questions from last time and correct a couple minor errors. I also wanted to try some different techniques of listening to this satellite, including different frequencies and other antennas.
More information on the satellite here: https://usradioguy.com/satellites/meteor-m-no-2-3/
More info on the image scanner system: https://en.wikipedia.org/wiki/Whisk_broom_scanner
This is the type of rooftop antenna I use, connected to an SDR and Raspberry Pi computer: https://usradioguy.com/wp-content/uploads/2020/05/20200307-How-To-Build-A-QFH.pdf
This is my current favorite software-defined radio for general experimenting: https://www.rtl-sdr.com/rtl-sdr-blog-v-3-dongles-user-guide/
For better 1.7ghz / HRPT reception, I use a SAWbird+GOES filter/amplifier gadget: https://www.amazon.com/Nooelec-SAWbird-GOES-Ultra-Low-Applications/dp/B07K1M39H4/
The folding satellite dish is a "Cyberex CN7500". I don't think they've been made since the '80s, but this company makes something similar: https://sub-lunar.com/products
I'm mostly recording satellite signals on Linux using rtl_fm, with the following settings (these might not be the best in every situation, I'm still learning how to do this!):
timeout 15m rtl_fm -M raw -s 120000 -f 137.1M -E dc -g 48 -p 1 (right angle bracket) raw_dump.raw
I'm then using sox to create a wav file:
sox -t raw -r 120k -c 2 -b 16 -e s "raw_dump.raw" -t wav raw_dump.wav
And then I process that wav file with SatDump: https://github.com/SatDump/SatDump
I also tried streaming from my computer with the SDR and antenna, using rtl_tcp as follows:
rtl_tcp -f 137.1M -s 250000 -b 16 -a (ip address)
And then connecting from the Recorder tab in SatDump. That seemed to work pretty well. I was told SDR++ works better as the streaming source, but could not get it to install on my Raspberry Pi.
More info on HRPT and antennas here: https://sgcderek.github.io/blog/beginner-hrpt-guide.html
I've also tried LeanHRPT, but I did my recording wrong for that: https://www.rtl-sdr.com/leanhrpt-a-set-of-tools-for-the-manipulation-of-hrpt-data/
(UPDATE: I heard that Meteor M2-3 switched BACK to 137.9mhz after I made this, but who knows which frequency they'll finally settle on).
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