BCD325P2/BCD996P2: Digital signals major broken audio

[videobruce]

Hard to describe, more than one 'digital' unrelated (non trunk) service will go into a highly broken audio receive, mostly garbled, completely non-understandable for a period of a few minutes.
It appears the services are unrelated to one another, discrete 'channels'. No real pattern to it. It only affects digital (P25), analog is ok.

Any idea here as it sounds as a internal defect. This started a week or 2 ago and is intermittent (of course).

 

[doctordialtone]

Any idea here as it sounds as a internal defect.

Do some reading on "Simulcast Distortion".

BCD325P2/BCD996P2: - BDC996p2 reception problems

Need some suggestions. I have a Uniden BCD996p2 installed in a vehicle. After getting it programed using Free Scan it works perfectly sitting in the driveway at my house. When I drive to the city where I work that's 10 miles away I get a NFM while I'm within the city limits. If I go outside the...

forums.radioreference.com

It comes up daily on this site.

 

[900mhz]

Sounds like a bit error problem. It is concievably possible that there is some sort of RF interference affecting the frequencies you are trying to hear. I have experienced a similiar circumstance a few times...a distant signal on the same frequency was the culprit. Another time, it was caused by intermodulation products. Give a listen to the affected frequencies in analog to see if you hear any activity.
You stated non trunking. Do you know if what you are attempting to receive is a single site, or simulcast type set up?

 

[videobruce]

At least one of the affected frequencies has no 'analog' duplicate. AFAIK, they are single sites, but it's hard to tell since it's very hard to stop the scan due to the very short activity.
Yes, I have read into this SD.

When it happens again, I'll have to take closer note of the affected frequencies if i can. One I'm pretty sure is a city service, none are fire or similar since I have no interest in any of those.

 

[videobruce]

W/O going too far OT, you mention BER, does MER also come into play here and is there equipment that measure either as there is for television; ATSC & QAM?

 

[900mhz]

W/O going too far OT, you mention BER, does MER also come into play here and is there equipment that measure either as there is for television; ATSC & QAM?

Oh yes, there is equipment to measure for MER/BER for ATSC and QAM. I did that stuff for a living until February 2021...I retired after 33 years from the rat race. Digital modulation is digital modulation regardless of the service. I used to dwell on constellation patterns all the time, looking for something out of the ordinary. What I will say is this...the more sophisticated the modulation, the less headway for error and error correction. QPSK will work in the worst conditions, where a 256 QAM signal under the same conditions will fail miserably.