$20 P25 Trunking Scanner (Part 4)

SDR

With op25 successfully decoding the control channel, now you just need to set up the trunking configuration. To do this, you’ll probably need to set up three files: 1. trunk.tsv defines the sites to be monitored. 2. site_name.tsv provides a table of talkgroup numbers and names for that site. 3. Because you probably only want to listen to a subset of the talkgroups, you can optionally create a file called site_name_wl.tsv with a list, one talkgroup per line, of the […]

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$20 P25 Trunking Scanner (Part 3)

SDR

The info in this and in part 4 was aided tremendously by several folks on the “op25-dev” mailing list. Without their help, I would not have even known where to start in getting my system running. I hope that what I’m documenting here will be helpful for others going down this path. If you’ve successfully installed Linux, Gnuradio, and op25 on your computer, you are ready to test the system, and then configure it for trunking. The scanner application is […]

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$20 P25 Trunking Scanner (Part 2)

SDR

Here’s how to install the OP25 scanning software. If you don’t already have Gnuradio installed on a Linux system, do those two things first. Any current Linux distribution works. I use Linux Mint which is very similar to Ubuntu. The easiest way to install Gnuradio is to use a script from the SBRAC radio astronomy group called build-gnuradio. Click on the link, then save the contents of the browser screen (easiest way is to select everything on the web page, […]

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$20 P25 Trunking Scanner (Part 1)

SDR

A couple of weeks ago at the Dayton Hamvention I bought a fancy Whistler TRX2 scanner that can receive the new P25 digital trunking system that’s been rolled-out statewide here in Ohio. Unfortunately, after a lot of attempts, I still can’t get it to reliably receive the talkgroups I’m most interested in. Out of frustration (and boredom) I decided to research the couple of projects I’d heard about to implement P25 decoding, and after a few hours work (and some […]

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