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esa / gr-opssat

This repository contains the UHF specifications and example applications for demodulating and decoding the received signal.
https://opssat1.esoc.esa.int/projects/amateur-radio-information-bulletin
GNU General Public License v3.0
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Which SDR to use and how adjust settings during reception #12

Open meteorkees opened 4 months ago

meteorkees commented 4 months ago

Hi got everything running. But... Did a few attempts today when ops-sat passed the Netherlands. No packets seen yet. I used the SDRplay RSP2pro sdr with the dual-band Arrow antenna (2m and 70cm). In the terminal I saw only zero's passing by....

3 questions:

  1. Which sdr to use? the SDRplay RSP2pro or a RTL-SRD V3 dongle?
  2. In the RX window I see two graphs. Blue is data 0 and Red is data 1. What does this mean, and should they overlap each other?
  3. What is the function of the 'Squelch' slider? I hear no audio at all. Does that mean that no signal is coming in and decoded?

Thanks in advance! pd2ch image

GuilhemHnr commented 4 months ago

Hello pd2ch, thank you for your interest!

I cannot open the gnu radio companion scripts right now, so I will come with more complete answers on monday for points 2 and 3.

  1. The SDRplay RSP2pro might need a specific sampling block in gnuradio. The gnu radio script used by the “Start UHF reception with RTL-SDR” should however work for the RTL-SRD V3 dongle. We can work on adding a script for the SDRplay RSP2pro, alternatively, you can look at the scripts in ./app-grc_script/lib and have fun by customizing it, this folder can be downloaded individually as a .zip in the releases. How to use this scripts are explained in the UHF campain guide - GRC Scripts

Best regards!

GuilhemHnr commented 4 months ago

Here are the answers to the other two points:

  1. Data1 is the signal from the SDR. Data0 is the spectrum of a perfect sinusoid at the satellite frequency, only used as a reference. The overlap is not perfect because the rtl sdr is centered with a slight offset.

  2. The squelch is only a threshold that can be used to reduce noise on data1. See the documentation here

Best regards!