[op25-dev] HackRF options ? More than this needed like the Airspys???

Graham Norbury gnorbury at bondcar.com
Wed Sep 9 11:26:40 UTC 2020


Honestly the best "documentation" is going to be the *example.json files
found in the apps directory.
A single "one trunked system with 3 feeds" can be seen in p25_example.json.

You don't have to use liquidsoap if you don't want to; there is the
built-in audio player and also the stand-alone helper app "audio.py". 
That said, we moved away from recommending darkice because of
reliability issues with the snd-aloop driver on Raspbian.

Graham

On 9/8/20 11:51 PM, op25 at zellners.com wrote:
>
> Quoting Graham Norbury <gnorbury at bondcar.com>:
>
>> On 9/7/20 11:19 AM, op25 at zellners.com wrote:
>>>
>>> OP25 doesn't work that way , and with out a major rewrite to do that
>>> you are better to just set a smaller bandwidth/sample rate as the rest
>>> is wasted processing.
>>>
>>> I set my op25 setups to be about 1MSPS or so as thats more than enough
>>> for things.
>>>
>> Sorry to disagree but op25 can and does work that way if correctly
>> configured under either rx.py or multi_rx.py.  In fact the multi_rx.py
>> implementation is designed to support an arbitrary number of trunking
>> systems and voice channel decodes using 1-to-/N/ SDR devices.
>
> Maybe this will settle this. ** I AM WRONG. ** Period.
>
> So where is the MULTI_rx.py documented???
>
> I've never seen or even heard of this.  Or documented at all really.
> Its all just letting it trunk from a CC like a scanner......Or this
> mode with a center freq...
>
> So lets discuss what it can do... you mention multiple CC and multiple
> audio feed...
>
>> liquidsoap...
>
> Yuck not really a fan.. ....but anyway....
>
>
> So lets start with 1 CC and doing MULTIPLE FEEDS????
>
> How is all this plumbed together to get this my IceCast server???
>
> Audio losses from "scanning" or this is queued up to feed in serial
> fashion?????
>
> One CC would need at minimum 5 feeds.... and how is all this audio
> held/queued up??? So if say 2 TGID's are active???? I can see issues
> trying this on a PI with the writes to an SD card right there.
>
>
>> , but the
>> penalty for going that route is having to deal with multiple antennas
>> (or a splitter) to try to capture an already marginal signal. 
>
> I have a dedicated yagi to point to one system. And fed through
> LMR400, low noise distribution amp to provide plenty of ports.
>
> Same with my setup for more localized system on an omni, LMR400, low
> noise dist. amp and multiple ports. More than I need really.
>
> Basically its the same setup you would see at the rx end of a site.
>



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