P25 One Frequency Trunk Question

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werinshades

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Chicago Fire Dept. EMS (Soon Fire), has permaantly switched to their new Digital System this past Sunday. They previously had a 30 day evaluation and noticed a potential problem that reared it's ugly head once we switched over again.

The system has to be programmed (in the XT series) as a P25 One Frequency Trunked System. However, the Dispatch and Mobiles each use a different Talkgroup ID, and if not programmed correctly by setting the Delay and System Hold to quickly jump off the transmission, you can easily miss or "clip" the beginning of replies. It's similar to listening to two different frequencies for mobiles and base.


I have one of my 996XT's dedicated to this system, with one System set for North and another for South. I haven't seen this issue addressed before ,and my question is their a "workaround" or a "default Talkgroup ID" I can use instead of programming dispatch and mobiles seperately? I know in my 796, you programmed 70000 as a Wildcard to receive Private Calls on a Trunking system. Is their something like that for the XT series for this type of system?
 

UPMan

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If there is no other traffic on the system, set it to ID Search (instead of ID Scan). However, you do still need to set delay to 0.
 

werinshades

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If there is no other traffic on the system, set it to ID Search (instead of ID Scan). However, you do still need to set delay to 0.

I do have Radio ID's in this system too. Just Dispatch and Mobiles is the only traffic on the system. I also have a 396XT, and it seems to behave differently. I've tried setting the System Hold as high as 4, and the Delay to 2, and it doesn't stay long on the system.
 

kma371

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This is why the one freq trunk option is worthless.

Why on a conventional P25 freq we can't see radio IDs without using this option is just plain dumb.
 

werinshades

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If there is no other traffic on the system, set it to ID Search (instead of ID Scan). However, you do still need to set delay to 0.

No difference doing it this way Paul. The main problem is two seperate Talkgroups for dispatch and the ambulances. The "quick replies" will get cut off. It's tolerable on the scanner I have dedicated for the system, but when I leave the house and use the 396XT, it's difficult to monitor. I researched others using these systems to see if anyone else monitors a system set up this way, so far haven't found one. Ideally...a "wildcard" Talkgroup ID would be the answer. Is that possible without a major firmware change?
 

RickLeb

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The system has to be programmed (in the XT series) as a P25 One Frequency Trunked System. However, the Dispatch and Mobiles each use a different Talkgroup ID, and if not programmed correctly by setting the Delay and System Hold to quickly jump off the transmission, you can easily miss or "clip" the beginning of replies. It's similar to listening to two different frequencies for mobiles and base.

I'm kinda new, so I apologize for the dumb question, but why does this have to be programmed as one frequency trunked system? If you want to hear all TG's anyway, couldn't you set it up as a conventional channel? I know it won't display the TG number this way, but are there any other reasons?.
 

garys

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I'm kinda new, so I apologize for the dumb question, but why does this have to be programmed as one frequency trunked system? If you want to hear all TG's anyway, couldn't you set it up as a conventional channel? I know it won't display the TG number this way, but are there any other reasons?.

Stop making sense.
 

werinshades

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I'm kinda new, so I apologize for the dumb question, but why does this have to be programmed as one frequency trunked system? If you want to hear all TG's anyway, couldn't you set it up as a conventional channel? I know it won't display the TG number this way, but are there any other reasons?.

Yes...that's an option of course. But...this scanner is capable of displaying Talkgroup and Radio ID's so i'd cetainly like to tke advantage of this feature. The scanner origianly came out with this feature for this type of system, then the Radio ID display feature was later added. If their was a way to just put in a "wildcard" Talkgroup in these type of systems, with this type of set up, it would solve the issue I inquired about. Thanks for the suggestion...
 
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