gqrx VS op25

There's an issue open for this: https://github.com/gqrx-sdr/gqrx/issues/1104

I could really use some help from a software build expert. Gqrx and all its dependencies would need to be built in CI with Apple silicon support, and I don't know how to do that.

If you don't need the web interface and your usual desktop SDR software supports rtl-sdr tcp mode, you can easily set up a small board that calls rtl-sdr with the appropriate parameters so that it will wait for a remote connection from the above software, not unlike what happens with WebSDR, but you would be using your usual desktop SDR application which would be native and much more snappy than a web browser. Here's an example using gqrx.

https://www.youtube.com/watch?v=74jDcHuDCmE

https://gqrx.dk/

GQRX works pretty well for me. There is also CubicSDR and SDRAngel afaik - you might just want to play around with them and see which you are most comfortable with.

SSB/CW (also (W/N)FM/AM/Raw) using GQRX

For most signals (including analog AM and FM modes) you can use a laptop with an RTL-SDR USB dongle (fairly cheap), or another SDR, and a reasonably tuned antenna. Various RTL-SDR models can tune from around 500 kHz up to 1.75 GHz with 3 mhz of bandwdith, and works with free software like SDR# for Windows and GQRX for Linux. It works with lots of other software, too, for ham modes, digital modes, etc.

Some of the Crossfire modules have a rudimentary spectrum analyzer function on them that might help you identify if there are other devices operating in the 900MHz band around that area, but I'm not sure the nano TX is one of them. I have a couple RTL-SDR dongles or equivalent I'd use with GQRX as a cheap spectrum analyzer if possible.

Good old GQRX for me https://gqrx.dk/

There is loads of software that will work such as SDR++, GQRX, CubicSDR, and SDRangel just to name a few. For HD radio reception, there is nrsc5. Nrsc5 only works with an rtl-sdr, so you will need one if you want to receive HD radio.

looks like it may not be able to do what I want it to do according to this. https://github.com/boatbod/op25/issues/184

I have no experience with DMR myself, but my understanding is that the Boatbod fork of OP25 has experimental DMR support, and I believe SDRTrunk software does, too.

Using OP25[1] with RTL-SDR dongles to implement scanners for trunking P25 radio systems on a computer. And as a sidebar to that, listening in on geographically remote public safety radio systems using Broadcastify[2]. It's basically the old "radio scanner" culture, but taken online and distributed worldwide. People listen to all sorts of stuff, but given my background as a former firefighter and former 911 dispatcher, my main interest is listening to public safety dispatch stuff.

That said, another commenter below mentioned modern "phreaking" and how it's become more radio centric... and while I won't admit to doing anything illegal, let's just say that there's some interesting stuff you can do / look at / listen to these days, especially with ubiquitous and inexpensive SDR hardware and related resources. See the recent story about the KrakenSDR passive radar stuff, and some of the papers that are out there about P25 security flaws, some of the automobile hacking stuff that's RF based, etc., etc. There's a fascinating world out there buzzing around on invisible electromagnetic fields... and you can tap into it with a $30 dongle and a Raspberry Pi (or your PC).

[1]: https://github.com/boatbod/op25

If it's P25 Phase I or Phase II then SDRTrunk might work. boatbod's op25 might be another option, but more complicated to set up.

I don't have a full guide for you, but I use https://github.com/boatbod/op25 for receiving and decoding P25 Phase 1 digital signals on the command line.

op25

If you are handy with Linux you can use an RTL-SDR and OP25 on a Raspberry Pi or really any PC. This is the page for the Fairfax trunked system https://www.radioreference.com/apps/db/?sid=6957. Any talkgroup with mode D can be listened to, mode DE is encrypted. If you want I already have config files made up for the police dispatch and fire/ems dispatch channels.