Streaming multiple TGs using SDR dongles and linux with a liquidsoap queue

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northernsummit

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A few months ago I posted a write up in the SDR forum on what Trunk Recorder was. Trunk Recorder is basically an application based on OP25 and GNURadio that listens to an entire digital system (all CC & voice channels simultaneously) and outputs .wav files into a directory for any or all TGs on the system, getting 100% of the transmissions less those you tell it to ignore.

I wanted to find a way to selectively take those .wav files and push them towards a Broadcastify stream. I pulled it off with liquidsoap and a python script that decides on a case-by-case basis if the latest transmission to be written to disk is meant to be streamed or not.

So for 3-4 SDR dongles (based on how wide your system's channels are spread out) and a machine with some modest CPU power you can stream just about anything. Want to source from two different systems but not miss any transmissions? Not a problem. Even better, Trunk Recorder now supports conventional analog so you're not limited to just streaming digital systems where it makes sense to mix and match.

This feed is using this solution: Macedonia, Northfield Village and Sagamore Hills Police, Fire / EMS

Here is a wiki write up on the whole concept:

Streaming with Trunk Recorder and Liquidsoap - The RadioReference Wiki
 

AB5ID

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Aug 6, 2007
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Lee's Summit, MO (Kansas City)
A few months ago I posted a write up in the SDR forum on what Trunk Recorder was. Trunk Recorder is basically an application based on OP25 and GNURadio that listens to an entire digital system (all CC & voice channels simultaneously) and outputs .wav files into a directory for any or all TGs on the system, getting 100% of the transmissions less those you tell it to ignore.

I wanted to find a way to selectively take those .wav files and push them towards a Broadcastify stream. I pulled it off with liquidsoap and a python script that decides on a case-by-case basis if the latest transmission to be written to disk is meant to be streamed or not.

So for 3-4 SDR dongles (based on how wide your system's channels are spread out) and a machine with some modest CPU power you can stream just about anything. Want to source from two different systems but not miss any transmissions? Not a problem. Even better, Trunk Recorder now supports conventional analog so you're not limited to just streaming digital systems where it makes sense to mix and match.

This feed is using this solution: Macedonia, Northfield Village and Sagamore Hills Police, Fire / EMS

Here is a wiki write up on the whole concept:

Streaming with Trunk Recorder and Liquidsoap - The RadioReference Wiki
This is great! Are any of this set-up in a busy metropolitan area?

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northernsummit

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This is great! Are any of this set-up in a busy metropolitan area?

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Just using Trunk Recorder on a busy system? Yes. I know for a fact that there are numerous Trunk Recorder servers setup recording numerous MARCS sites in Ohio. Those are not necessarily being streamed, but it can keep up.

In terms of busy TR sourced audio being fed, yes all of the Cleveland, Ohio individual district feeds are using this approach. Their listener count is a little low probably because they've been offline for a week. But thats a single talk-group per feed I believe.

See: Cuyahoga County Ohio Live Audio Feeds
 
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