Double SDR setup

Hey guys. Just starting with my groundstation (no rotator version + RPi 3) I’d like to know how many SDRs/Antennas is the RPi3/software able to handle? I mean not at the same time, but in general? Like I would want to build a station with a 2m and 70cm antenna connected to it. Is it possible? Or would I have to have a RPi3 for every antenna?

Excuse me if this was answered before. Just point me to the right link if there is one.



You have different options there. The most straight-foward one is to use a diplexer for the two antennas. Other options include hacking the client to use 2 rtl-sdrs in one RPi3

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Has this been done before, hacking the raspian to use 2 SDRs? Just curious, since I‘m completely new to this? Does anybody run such a 1xRPi3/2xSDR station?

From the gr-satnogs perspective this is totally possible. You have to select the proper RTL device using the --dev-args parameter.

E.g --dev-args='rtl=dev_index' where the dev_index is the device index of the corresponding RTL device (0, 1).

@Schinderberge There was a setup with two SDRs, and there was an incomplete guide with what was needed to be changed in order to get to clients running at the same time on the same device. I’ll try to find the link for this guide in my logs and I’ll added it in this post.

You will need to go manually and install the clients and whatever is needed as the satnogs client image doesn’t cover a setup like that.

What worries me in this kind of setup is that rpi cpu will be probably not enough for two SDRs/gnuradio scripts running at the same time. But you can always try it and let us know the results. If you have gr-satnogs installed then you can try it by running twice, one for each sdr, the command that @surligas gave in his post.

If it doesn’t work then you can go either to a x86 solution or to a two rpis setup. As @pierros said another solution is to use a diplexer and one sdr and having one station with two antennas.

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Well that sounds interesting. The thing is the RPi3 wouldn’t have to run both SDRs/antennas at the same time. I guess that would be indeed too much for the cpu.

But I thought more along the way that there would be this pool of jobs waiting, like for 70cm and 2m and the software would decide which SDR it will need depending on the kind of satellite/frequency it has to observe.

As I said, can’t wait for the things to come. :+1: