DOITT UHF P25 Trunked System

[CqDx]

Hi all,

For a few weeks the followings has been on the air with various coverage testing done at various locations around the city, it seems like it is a extension to the DOITT 700 MHz System as it shares the same system ID and the bandplan of the 700 MHz system also shows UHF channels:

System ID: 3A8
WACN: BEE00
RFSS: 1
Site: 30

483.49375 Control Channel
481.68125 Alternate Control Channel
483.24375 Voice Channel
483.36875 Voice Channel

 

[radioman2001]

Maybe expanding the 700mhz core to UHF for pure P-25 trunking ( phase II ?). The UHF 3600 bd system is EOL since it was built, as I heard it they cobbled together the last remnants of parts to build it.

 

[CqDx]

The 3600 baud system has been on the air for almost 10 years, it makes sense for electronics to go obsolete.

 

[GTR8000]

Eventually both 3600 systems will go away, and the 3A8 system will handle it all. No brainer getting everything on the same core and zone controller, as it makes operating across bands so much easier. The ASTRO 25 system doesn't really care what frequencies are being used by the repeaters, all system activity and voice gets funneled through the same zone controller.

PS - That 481.68125 frequency is licensed to Westchester County, not DoITT, so it was likely temporarily borrowed for testing purposes to reduce the amount of active frequencies taken from the existing C820 UHF system.

 

[CqDx]

It seems like the 481.68125 Alt Control Channel is no longer reported and it is now reporting 483.35625 as the alternate control channel.

 

[GTR8000]

That makes a lot more sense.

 

[newsnick175]

Could this system be a backstop if the T-band freeze waiver is not successful. Could it handle the cops and the fire department ??

 

[GTR8000]

Could this system be a backstop if the T-band freeze waiver is not successful. Could it handle the cops and the fire department ??

Well, we're talking about the T-Band simulcast cell of the 3A8 system in this thread, so how would that solve anything related to the T-Band giveback?

I think many people are unfortunately completely misinterpreting that waiver in the other thread about NYPD. It's not any sort of blanket T-Band waiver to continue operating beyond the T-Band giveback. It was merely a waiver requesting a very specific modification to a single T-Band license, as back in 2012 the FCC decided to freeze processing new or modifications to T-Band frequencies due to the eventual giveback. Believe me, that waiver was nothing special or noteworthy when it comes to the big picture. In fact I'm personally aware of a couple of those types of T-Band waivers that have been quietly granted since 2012, nothing was earth-shattering about them.

 

[CqDx]

Also as someone pointed out, PD has always maintained their own radio shop with their own techs. This is a DOITT system and a decade ago FDNY and EMS decided to have some of their radio resources on the DOITT maintained infrastructure as a subscriber. FDNY and EMS are already daily users of the DOITT system, but I don't see any reason why PD would migrate to DOITT managed infrastructure.

 

[GTR8000]

To be blunt, the bottom line is that FDNY and NYPD would rather thumb their nose at the FCC than abandon T-Band, so it's going to be very interesting if the giveback is not rescinded by Congress and it goes into effect. Like I've stated once before, the attitude NYC is going to have is pretty much "Come at me, bro" as far as any punitive action the FCC might take at that point.

 

[radioman2001]

Schumer is making noises again about the giveback and trying to negate it, but he only was seen talking with Westchester Fire Companies in this latest press release.

NYC will just send to DC 200 lawyers and beat Congress up again to keep the channels they got from Congress after 911. There isn't enough bandwidth on 700 to make up for the possible 42mhz of T-Band giveback.

There was also the thought of removing all TV stations nationwide to make them P.S. without interference, which has been a major issue here in the tri-state with weather inversions. It didn't float well with the FCC in 2012, but now maybe.

 

[richee2000]

now that these uhf channels have been added, I am receiving this system for the first time here in somerset county nj... however, i am only getting radio techs testing, .. no other system traffic... are the uhf voice channels being used for regular radio traffic??

 

[CqDx]

It is still under testing, no real traffic on the system yet

 

[richee2000]

Understood. ... Are UHF and 700 frequencies being used at the same transmitter sites? Any clue where these sites are?

Sent from my SM-N960U using Tapatalk

 

[richee2000]

the RR database shows quite a few talk groups for this system.. you say none of these are active??

 

[GTR8000]

Understood. ... Are UHF and 700 frequencies being used at the same transmitter sites? Any clue where these sites are?

Both sites are simulcast cells, made up of multiple physical sites. Click on each site in the database, then look at the Site FCC Licenses list. If you click that little icon it will show you the locations of all licenses combined on the map. That will give you an idea of where the transmitters are licensed.

the RR database shows quite a few talk groups for this system.. you say none of these are active??

Not yet active on the UHF cell, that's correct. Remember that this system has two simulcast cells, the 700/800 which has been operational for a while. UHF has just begun testing and is not carrying any regular traffic yet. May not for quite some time, as the UHF Type II system is still very active.