BCD536HP: Unit ID accuracy

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N0BDW

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Background:
* P25 Phase 2 Motorola system (this one)
* BCD536HP running v1.11.23 firmware [UPDATE: now running 1.11.31, same issues]

Problem:
Units will key up and their unit ID will show. If the dispatcher (or another unit) is quick and keys up right at the tail end of their transmission the scanner doesn't see the change in ID. The ID from the first unit continues to show, despite the fact they are no longer talking and another unit is now talking.

Motorola APX radios properly show the change.

In addition for some very brief transmissions, such as if someone just clicks the mic, or gives their unit ID to get the dispatcher's attention, their ID is not displayed on the scanner (but is on the APX radios).

Is there any setting that might help with this, or is it something that could perhaps be addressed in a firmware update?
 
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jonwienke

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Post in that thread exactly what issues you're having.
 

N0BDW

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Video: https://youtu.be/hkEwIL68H58

You can see the NYSP unit keys up and their ID is displayed. Then the dispatcher keys up right at the tail end of their transmission. The dispatcher's ID is not displayed (SP ID continues). SP keys up again, and their unit ID continues. Then there is a pause, dispatch keys up, and their ID is displayed.
 

GTR8000

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It's been addressed in the beta firmware. Try updating to .31 and see if the issue persists.

https://forums.radioreference.com/2778626-post483.html
No, it hasn't. The post you linked to has nothing to do with missed initial call grants on P25 systems, which is the issue N0BDW is talking about. Please read carefully before posting.

Ben, that issue has been around for many years, going back to the XT series. The trouble is that the scanner is not processing the initial call grant, which is where the UID is broadcast. If the scanner doesn't see the call grant, you won't see the UID displayed. Which means that in a series of transmissions that take place back to back on the same voice channel, the original ID will "hang" until the scanner sees and correctly processes a new grant.

While the APX is much better at seeing all of the grants, it's certainly not 100% perfect, and from time to time can also miss a grant or two, resulting in the same behavior.

So to sum up, from a technical perspective: the UID is only contained in the initial call grant, which is broadcast at the start of a transmission. If that is missed, which it could easily be, the scanner won't display the UID until a new grant comes along that it sees.
 

Jay911

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The trouble is that the scanner is not processing the initial call grant, which is where the UID is broadcast. If the scanner doesn't see the call grant, you won't see the UID displayed. Which means that in a series of transmissions that take place back to back on the same voice channel, the original ID will "hang" until the scanner sees and correctly processes a new grant.
I knew this was the case on analog channels on Type II systems, but does not the P25 CAI carry the UID on all voice transmissions? I was pretty sure it did on phase 1 calls, but I am not sure about phase 2.
 

GTR8000

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I knew this was the case on analog channels on Type II systems, but does not the P25 CAI carry the UID on all voice transmissions? I was pretty sure it did on phase 1 calls, but I am not sure about phase 2.
I'll have to double check the TIA docs, it's been a while since I've combed through them.

I should've been more clear that I was primarily referring to the call grant on the control channel, which only broadcasts the ID during the initial grant, not during the continuations. However of course once the scanner/radio is on the voice channel, the control channel is irrelevant as far as those grants. It would at that point be decoding the low speed data stream on the voice channel for the duration of the conversation (including, of course, which other priority enabled talkgroups are active...something else the Uniden scanners fall short on doing with Phase II systems).

You know, Jay...your post just reminded me of the P25 TDMA priority bug with the Uniden scanners. I have a feeling these two are related, with the cause being that the 996P2 and x36HP scanners are not correctly decoding the low speed data stream on Phase II voice channels.
 

Jay911

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I have a feeling these two are related, with the cause being that the 996P2 and x36HP scanners are not correctly decoding the low speed data stream on Phase II voice channels.
That was what I was thinking, though I don't have a Phase II system near me to test the theory on.
 

N0BDW

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I wonder if it is not decoding the unit ID if that information is passed over a voice channel, instead only decoding it from the control channel. Would that add up?

Edit: It seems as though that may be essentially what GTR8000 was getting at.
 

marksmith

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The Uniden radios have done this forever. The radio still obtains the UID the same on digital or analog systems even though those systems might have info in voice channels or otherwise available.

Unitrunker will obtain proper UID on either digital (1 or 2) or analog systems at change of user, regardless if repeater stays up. Different for radios since they started UID tracking with 96xt radios with a firmware update. The x36 radios initially would not do UID.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
 

troymail

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From my experience, no scanner (and no firmware version of any number) seems to do this correctly 100% of the time. In fact, even my Unication G4 sometimes doesn't provide a radio ID.
 

N0BDW

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From my experience, no scanner (and no firmware version of any number) seems to do this correctly 100% of the time. In fact, even my Unication G4 sometimes doesn't provide a radio ID.
I don't expect perfection. Even the APX radios are not perfect. But this happens with significant regularity, making the display of unit IDs much less useful.
 

chill30240

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I don't expect perfection. Even the APX radios are not perfect. But this happens with significant regularity, making the display of unit IDs much less useful.
I have the exact same problem and feel the same way. I never have a problem with the TG's it's always the UID's. The FW doesn't seem to matter either. I've run .17 to .31 and the same problem happens.
 

phask

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Maybe related, but the replay on the 536 is terrible with UID's. A HP1 seems nearly perfect on the same system.

I occasionally run a spare HP1 24/7 just to discern UID's. They change for his system as well as new units coming online.

Honestly have not tried using the 536 record feature to see if any better than replay.
 

chill30240

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Maybe related, but the replay on the 536 is terrible with UID's. A HP1 seems nearly perfect on the same system.

I occasionally run a spare HP1 24/7 just to discern UID's. They change for his system as well as new units coming online.

Honestly have not tried using the 536 record feature to see if any better than replay.
The replay on the 436 is terrible to. I thought I would populate my UID list from replay, forget that. It's no better than live. The only thing that seem to never fail is the on/off button.
 
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DaveNF2G

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Me, three.

I was visiting western NY over the weekend and left my 436 on recording the Monroe/Ontario system all night. On replay, I saw UIDs only occasionally, and that was always on dispatcher transmissions. What I would conclude from that, absent other input from local monitors, is that only the dispatch units are assigned UIDs, or that the mobiles are being patched in from elsewhere. I suspect that neither is true and it's the scanner. :)
 

N0BDW

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Me, three.

I was visiting western NY over the weekend and left my 436 on recording the Monroe/Ontario system all night. On replay, I saw UIDs only occasionally, and that was always on dispatcher transmissions. What I would conclude from that, absent other input from local monitors, is that only the dispatch units are assigned UIDs, or that the mobiles are being patched in from elsewhere. I suspect that neither is true and it's the scanner. :)
We work with the Richmond FD in Ontario County fairly regularly and I can confirm that their Harris radios show the UIDs properly, so it isn't the system -- it is the scanner.
 
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