P25 One Frequency Trunk Programming

[JASII]

I have a couple of questions about programming my Uniden BCD996XT for One Frequency Trunked channels. I have a f frequency programmed that way now and it displays the NAC code as ID search, but I don't get Unit IDs to display. Does anybody have any idea what I need to change so that it displays Unit IDs?

Also, is it possible to program multiple channels in a system for One Frequency Trunking? IF so, will it display BOTH NAC codes and Unit ID for each transmission that it receives? Also, it appears as if there is a limit of 255 channels. Is LCN significant or do I simply leave that blank for this since we don't need them for Motorola systems.

 

[SB-Wi]

Easier to Read BCD996XT Digital Scanner Manual
Disp. Unit ID (Requires firmware 1.04 or newer). Allows you see the unit ID of the radio currently transmitting on Motorola, EDACS, and APCO P25 systems. Scroll to 'Disp. Unit ID' and press E/

.
Scroll to On or Off and press E/

to save and exit.


For multiple frequencies, create each one as a separate site within the system. All sites in a system share the unit ID's and talk groups (if any) and you are limited to 256 sites per system, but if you need more just create another system. This is a conventional system (not trunked) so LCN and Motorola are irrelevant. Check your system type as there shouldn't be an entry for LCN in a P25 system.

 

[JASII]

Thank you for the reply. Sure enough, right after posting this I realized that the global Unit ID was off. It is on now and working properly!

 

[JASII]

.....For multiple frequencies, create each one as a separate site within the system. All sites in a system share the unit ID's and talk groups (if any) and you are limited to 256 sites per system, but if you need more just create another system.....

I tried setting up a system with one frequency per site, but it will only follow the first site. Have you actually been able to get it to follow multiple frequencies with one frequency per site?

 

[SB-Wi]

I tried setting up a system with one frequency per site, but it will only follow the first site. Have you actually been able to get it to follow multiple frequencies with one frequency per site?

I haven't done this myself but I'm sure I read a thread about it. Try searching the Uniden forum.

 

[SB-Wi]

Found this:
http://forums.radioreference.com/un...-one-frequency-trunk-vs-conventional-p25.html

By the way, regarding programming it as a "one frequency trunk" vs a "conventional" channel.

Uniden, for whatever reason, treats what the rest of the world knows as "conventional P25" in two different ways. You can program a channel as a "conventional" channel with P25 audio, and get all transmissions that match the NAC you program in (or, if you don't program in a NAC, all transmissions period). However, P25 CAI (Common Air Interface, another name for "P25 audio", essentially), also carries the numeric ID of the radio and the talkgroup. So technically speaking, it is like a trunk, but one without a control/data channel.

If you program a frequency as a "one-frequency trunk", you can receive not only the audio transmissions, but see the talkgroup ID and radio IDs in use. You can also give labels to them, just like a "normal" trunk system. I guess that's probably the reason Uniden does it this way.

As to why you didn't hear anything when you programmed it that way, I have no idea. Every time I've programmed up a "one frequency trunk", I've gotten it to work. I don't put in the NAC - I just leave it at "NAC Search". Also make sure that "ID Search" is enabled - that might have been your downfall. I've even been able to put multiple frequencies in a "one frequency trunk" system, both by putting multiple frequencies in one site, and by putting multiple sites in a "one frequency trunk" system. The latter makes it easy to manage radio IDs if one agency uses a bunch of conventional frequencies, although you lose the ability to identify what actual frequency they're using.

 

[SB-Wi]

And these:
http://forums.radioreference.com/uniden-scanners/255804-conventional-p25-radio-id-display.html

All of the Unidens I've worked with from the T series (396T/996T) up thru the HomePatrol treat a P25 conventional channel as "one frequency trunk" if you want to see radio IDs and talkgroup IDs. GRE scanners do not - they will display that data if the channel is just programmed "normally".

The good news is you can program multiple frequencies into a "one frequency trunk" system, either as one site or multiple sites, so if you have a batch of frequencies that will all have the same talkgroup and RID info (say if an agency has a handful of conventional P25 channels), and you don't mind not knowing which frequency the info came from, you can do that.

I have the KSP set up as a regular system on my 396XT. The one frequency trunk is very annoying. If the KSP uses the same TGID on every channel, the alpha tag will always be the same. I only use one frequency trunk for things like the TSA and other small towns that use it repeated. Uniden should release an update that allows radio ids to be seen even on a P25 channel programmed in a conventional system.

Jacob

Actually, the PSR-800 is the only GRE scanner that can display radio and talkgroup IDs on P25 conventional channels. The PRO-197/PSR-600 will only show them on trunked systems.

And yes, the whole "one-frequency-trunk" thing on Unidens is extremely annoying. In addition to scanningisfun's observation, I have noticed that it adds a few tenths of a second to the decode time, resulting in the first part of transmissions getting cut off. Overall its just a very clumsy way of doing something simple, and doesn't work well.

 

[SB-Wi]

This is the best yet:
http://forums.radioreference.com/uniden-scanners/234361-p-25-one-freq-trunk.html

I have programmed into my XT about 20 different P-25 One-Freq Trunk channels. They belong to 2 different agencies. Not a problem with that however I have each frequency programmed as it's own system. My question is can I add more than one P-25 One-Freq Trunk channel into one system if it's for the same agency to keep it simple? Can I have 10 frequencies in 1 system and 10 in the other? Will it work that way or must I have each freq. in as a P-25 One-Freq Trunk System? Instead of 20 different systems in the scanner I would like to just make it into 2 systems. As I am programming in by hand I am asked if I would like to add another channel to the system. I am really not sure how the it works to tell you the truth...

Yes, After you set up a single channel P-25 system you can add different sites ( Frequencies) to the system.

Or you can add all of the frequencies to one site.

Jacob

I have 280 freqs in one system - all my fed freqs- scans right by the encrypted stuff and only stops on clear xmissions
Best thing since sliced bread

 

[JASII]

Thank you for the replies. I did ended up re-initializing the scanner and now it follows it like I had hoped. One other thing, should it display the NAC Codes while in the P25 One Frequency Trunk mode?