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New Pro-651 and Pro-652 units. The newer Pro-651 is the same unit as the older Pro-106 portable.

I am able to hear stations using P25 and indicates the NAC, but both units are not "Decoding" the voice - on certain frequencies/stations. Just getting the under water garbage. Am I hearing P25 phase 2 ?

Some P25 stations work and others I just get the under water garbage -- but I do get the NAC Code.

The NAC is repeated fairly often in the data stream, so if you decode anything at all it'd probably be that.

Sounds like you're experiencing high bit error rate. Signal quality can obviously cause that, but multi-path will as well. Digital hates multi-path. Are the stations you're not able to fully decode in a different band than the ones you can?

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I taste copper.
Comments, views, opinions - and trails of destruction - are my own.

Having problems with a few VHF and UHF stations.
Lots of local P25 stations are fine. (Both VHF + UHF). Just a few Federal systems that I am having problems with. Yet I do hear alot of other
USFS / NPS and BLM P25 traffic.

Could it be: 1.) Station signal level -- low signal level , or multi-path or
2.) P25 phase II ??

If it's a P25 phase II station -- should I be able to decode the NAC -- or not -- without decoding voice ??

As I understand, those models are the same as both the PSR500 -- and the PSR600 -- neither of which even do Phase-2 P25. I have both, and neither even register that there's Phase-2 traffic occurring.

Also -- unless I'm badly mistaken -- and I often am -- you can't get Phase-2 on a VHF or UHF conventional system -- trunked only.

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President-in-Exile, Seattle Area Radio Communications And Scanner Traffic Intercept Crew (SARCASTIC)
Don't feel bad if you can't use your STD100/200; there are still people using Digital Frequency Search!
Bunnery definition for the under-fives

Thanks guys. I think it's just a poor signal (Low or multi-parh)
that prevents decoding the voice. I get a good NAC indication.
The few channels I have problems with - are federal and are
not trunked. Thanks MTM

If you are just hearing the under water garbage, most likely its's encrypted. NACs will still decode with encrypted traffic...

- Chris

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Chris Parris
Federal Wavelengths columnist
The Spectrum Monitor Magazine
chrisparris@thefedfiles.com

BOOM. Ton of Bricks just hit me on the head. Thanks Chris.
All of the frequencies that I am having problems with are Federal. All of the local PD stuff work fine.