Project 25 system questions.

[HarryWilly]

I am trying to get a P25 monitoring station on the cheap using old scanners and a more or less junky computer. So I have a couple of questions:

1. Does the radio need to support P25 in order to decode the trunk channel stream or will any radio with a discriminator tap work?

2. If you use one of the supported radios (I haven't looked yet, but I assume it uses supports non-p25 ones) can you feed a discriminator tap'd feed to a program on your computer to decode the audio as the program flips channels to monitor an active conversation?

I know it might be easier to use a digital scanner in this situation, but I don't have one yet (don't have many systems I have to hear). I know when I get one *cough* BCD996XT or whatever they call it *cough* it will be a mobile install, so I thought it might be easy to use old equipment I have lying around.

Thanks in advanced.

P.S. if someone such as UPMan were to see this - Black face please!!! And multiple backlight like on the BCD396XT!! It will look better on more mobile installs.

 

[FlashP]

No such luck

Any radio with a proper discriminator tap will handle a P25 control channel, to watch on the screen or tune a second receiver. I haven't heard of a readily available PC software package that would decode P25 audio for you - a 396/996/etc is required. WinRadio has a P25 option, but you have to use their hardware.

Flash

 

[HarryWilly]

Good enough answer for me...

There is software for audio - so far it appears to be commercial only and quite expensive. But it is an open standard (Common Air Interface at least) so if someone wants to tackle it, it would be possible to decode the packet data as it comes in. I am sure it would require a data slicer, then that data could be decoded, but UniTrunker does kind of show that it is possible to decode data packets without a data slicer. I think hardware decoders do it the best though so I may have to sell of some used stuff towards a digital radio