can't lock on P25 control channel

[RF23]

Good news folks! I can report that i`ve found a workaround to the problem of no lock on c-channels at least on the `436HP. What i did was to go into MENU>SETTINGS> band defaults, change any (or all) of these from NFM to FM, did this with the system i was monitoring (a P25 trunked system) and now have stable lock & track, will test further, but for now it appears that this issue affects reception of P25 TRS`s in the NFM mode only. I`ll update later on with the results . N9NRA

It is very good news indeed that you found the solution to your problem but I thought the very first thread on this sub forum namely "test-p25-decode-improvement by switching from NFM to FM" was to help develop a firmware fix for this problem. Do you have the latest firmware, it should have fixed this for you?

If you do have the latest firmware you might consider posting in the above mentioned thread so Uniden and others will know that the firmware update did not fix the problem for everyone since it did not change your NFM to FM for you.

In my case if makes no difference in P25 decode but like you a lot of people saw a big improvement when they switched from NFM to FM. However, I do not know why changing from NFM to FM would have such a large effect on P25 cc decode.

 

[N9NRA]

It is very good news indeed that you found the solution to your problem but I thought the very first thread on this sub forum namely "test-p25-decode-improvement by switching from NFM to FM" was to help develop a firmware fix for this problem. Do you have the latest firmware, it should have fixed this for you?

If you do have the latest firmware you might consider posting in the above mentioned thread so Uniden and others will know that the firmware update did not fix the problem for everyone since it did not change your NFM to FM for you.

In my case if makes no difference in P25 decode but like you a lot of people saw a big improvement when they switched from NFM to FM. However, I do not know why changing from NFM to FM would have such a large effect on P25 cc decode.

Short update, the idea i tried this morning works . Switch from NFM to FM for P25 TRS`s and all is well. I`ll post in that forum so everyone else knows this too . N9NRA P.S. And yes, i do have the latest firmware (1.03.00) on my `436HP.

 

[dmdx86]

fixed

I found the fix for my issue - it wasn't switching from NFM ->FM in the band defaults that did it but rather manually adjusting the P25 Threshold Level.

My own misunderstanding of what that feature was supposed to accomplish kept me from trying that earlier (namely the fact that it *does* actually affect control channel reception, not just the quality of voice data decoding).

Changing the value to "6" seems to leave the DAT icon lit about 95% of the time. I am not missing any conversations that I can tell.

 

[Ghstwolf62]

That seems to be the general consensus. Its also system specific so basically everyone has to find that sweet spot that works for them vs a general setting of it.

 

[Granite8]

The City of Lubbock has started a 3 year process of moving from EDACS to Harris P25. Right now, they are simulcasting several police, fire, sheriff and a few other channels. The P25 is LMR and the audio is of a variable quality, about a third of it poor. I am trying to build a current Ubuntu/GNUradio/OP25 system. I have the first two working, but can't find an installable OP25 script. I noticed in this thread that Picco has OP25 on a laptop and says the LMR quality is good. I am an old Windows guy, and a newbie on Linux. Can anyone give me a hand in getting OP25 working here?