MPDC now simulcasting on the 800 system

[jkahn]

I sent a private message to Dewey, then decided I'd throw this out to the entire forum:

Does anyone know that MPDC is now simulcasting the 460 talkgroups on the 800 system too?

I was made aware of this while updating the 460 and 800 systems on an old BC250D.

On my 396 I have had all of the TGIDs in both systems and the only MPD ID I have heard on 800's was Citiwide 1 up through this past weekend.

Anyway, I updated some TGIDS on the 800 EMS/City system and dumped it back into the scanner.
Before I started scanning on the 250D it was sitting on the open control channel after programming and I heard some 6 & 7 D unit traffic on the 800 system, so I started scanning in ID search mode and lo and behold I was hitting all kinds of MPD TGIDs.

So,.....how long has this been going on? Is it very recent or have I just not heard it before?

 

[gesucks]

I sent a private message to Dewey, then decided I'd throw this out to the entire forum:

Does anyone know that MPDC is now simulcasting the 460 talkgroups on the 800 system too?

I was made aware of this while updating the 460 and 800 systems on an old BC250D.

On my 396 I have had all of the TGIDs in both systems and the only MPD ID I have heard on 800's was Citiwide 1 up through this past weekend.

Anyway, I updated some TGIDS on the 800 EMS/City system and dumped it back into the scanner.
Before I started scanning on the 250D it was sitting on the open control channel after programming and I heard some 6 & 7 D unit traffic on the 800 system, so I started scanning in ID search mode and lo and behold I was hitting all kinds of MPD TGIDs.

So,.....how long has this been going on? Is it very recent or have I just not heard it before?

All UHF talkgroups can be used on either UHF or 800 depending how the controller is set up. The controllers is usally set so that only one on all the time is Citywide 1. 1D-7D and their Tac's and SOD are usally only on when a radio affilates to that talkgroup. Some are set never to cross to the other band.

 

[dtscho]

I have noticed that some of the MPD channels are appearing on the 800 system over the past few weeks. 1D, 2D, and 3D in particular seem to be on the 800 system quite often.

Dave

 

[Samuel]

I too noticed recently that more of the police talkgroups were being simulcast. I first noticed it around the time of the G20 summit and thought it could be related to that but it has continued. Anyone have any rationale why they would want to simulcast them on 800?

 

[ka3jjz]

It's a bit far off, but how the upcoming inauguration? Or perhaps more likely someone forgot to drop the patch... 73 Mike

 

[Dewey]

As mentioned in the reply PM, PD and FD are normally treated as two sepaerate systems. However, I have occasionally seen a PD talkgroup or two simulcast on the FD system. After being asked about this, I have begun watching FD on Universal Trunker. Last night, I noticed that 1D, 3D, 6D and Citywide-1 were being simulcast on FD. While this is just a pure speculative guess at this point, I think I'm going to agree with Mike (ka3jjz), and say that this may have something to do with the upcoming inauguration. Maybe there are not enough UHF radios to loan out to the reported 4,000 officers being imported for the inauguration, so they are testing system loading on the FD system so they can loan out some FD radios for PD use as well. Again, just my guess after Mike's comment.

Dewey

 

[fireradio]

gesucks got it right. The two systems are tied together at the controller level, so that when an 800 MHz radio sends an affiliation request to a UHF talkgroup, the system broadcasts that talkgroup on 800 MHz until all 800 MHz radios monitoring that UHF talkgroup have deaffiliated.

 

[Dewey]

gesucks got it right. The two systems are tied together at the controller level, so that when an 800 MHz radio sends an affiliation request to a UHF talkgroup, the system broadcasts that talkgroup on 800 MHz until all 800 MHz radios monitoring that UHF talkgroup have deaffiliated.

I have no doubt about the operation of the controller. The part I'm trying to figure out is why would a FD radio be affiliating with PD talkgroups. I've never heard FD on PD channels, and have always known them to request assistance, even priority assistance through their dispatcher. The only reason I can think of for this is that the PD arson investigators and/or PD-FD IAD agent (a sworn PD member) have been given FD radios with PD talkgroups so they don't have to carry two radios. However, I still admit that I can be wrong. BTW, it is not a fluke, but some PD zones are still being broadcast on the FD 800 system as originally reported by Jkahn.

As a side note, when the PD radios are switched to one the two true Metro Transit PD channels, the PD radio actually deaffiliates from the 603d system, and affiliates with Metro Transit's 8209 system, complete with a new radio ID.

Dewey