InterceptRadio.com Forums

Question for the PSR-500/600 users:

How low of a signal strength can you succesfully decode P25 audio?

Reason why I'm asking:

With the BCD396T, I don't recall it having to have a "full" signal to decode P25 audio. It needed somewhat of a signal (1-2 bars) but it could still decode the audio.

With my BCD396XT, it seems that I need to have nearly a "full" signal to decode P25 audio. I need at least 4 bars to get any audio. I can see the TGID being displayed but no audio comes thru.

Now I'm starting to really understand the downside of a P25 system. On the 396XT, I can receive a Motorola Type 2 trunk (with audio) at ZERO bars! Yes, I said ZERO. It's scratchy and I may miss a word or two, but I can generally hear enough to decipher the transmission.

I'm just wondering if the GRE users experience this as well?

PS. I should note that the P25 audio that is decoded by the 396XT does sound quite a bit better than the 396T. The 396T had this 'garbled' P25 audio. I think Uniden employed more filtering elements into the P25 audio output on the 396XT.

Do any P25 scanners display received Bit Error Rate?

The 396XT does not.

I'm afraid I can't tell you - I've not monitored much of P25 and what I have had on federal I get surprisingly strong signals...

Yeah I was listening to the Pierce Transit system. I think the CC freq was 774.48125 or something close to that. My LP antenna is down temporarily so I was just using my discone antenna.

I get anywhere from 1 to 3 bars on that P25 system. I was getting some P25 audio yesterday but it was only at maximum signal peaks. Most of the time, I could see the TGID but I wasn't hearing any audio (this is when I was seeing only 1 or 2 bars on the meter.)

I just finally ordered an external antenna from the house. I'll see about the pierce transit system next time I have an hour to kill :-)

does any scanner decode DSTAR?

ICOM PCR1500 / 2500 both do this with plug in modules.

Although I do have to say, for all that cost why buy a receiver, when you can buy a transceiver for same (or less?)

Try tapping the volume knob during a transmission--as if you were going to change the volume level. Besides displaying volume level it also shows battery voltage and a couple of other things I can't think of at the moment.

Okay I found it. The XT version shows a "P25 Condition Mode" - when you push Func + Knob Push (do this twice in a row.)

This brings up the 2 bottom sub-menu lines on the display. This shows P25 Decode Error Rate and the Threshold values. Unfortunately, the PDF Reference doesn't give any real explanations.

On the Pierce Transit system today, I"m getting much better reception at times. For whatever reason, I'm getting 5 bars (full signal) on the control channel, but when audio comes thru it drops down to 2 bars... (the voice channel traffic is on 769mhz.)

As far as that mode, it's showing some wild numbers. At times, when the display shows a TGID, my decode rate is over 100. When audio is coming thru, it's down to around 25-30...