Philadelphia TRS / SEPTA Tunnels

[Audiodave1]

Hello,
Today I was in a location where I could use unitrunker on the PPD TRS.
I found it interesting that a peer was listed as site 6 using frequency 774.91875 as a CC, which is part of the Broad St line tunnel system.
Might this be the Market/Frankfurt line system online?

Dave

 

[PhillyPete]

Are Philadelphia’s 2 P25 sites actually simulcast?

I’ve been logging activity across all talkgroups in both of the Philadelphia P25 systems labeled as simulcast on RadioReference. Site 1 doesn’t seem to pick up any police dispatch talkgroups, but does pick up a few talkgroups that Site 2 doesn’t pick up at all (PPA, PHL Emergency). Both sites...

forums.radioreference.com

 

[PhillyPete]

Any talkgroups show up?

 

[Audiodave1]

Any talkgroups show up?

I was out of range, Just seen as a peer.

 

[PhillyPete]

I have zone 1 programmed for the city services and zone 2 for the police. I also have the broad street site programmed for both. I'm thinking that I should program the market Frankford site as well.

 

[Whiskey3JMC]

I'm thinking that I should program the market Frankford site as well.

Go for it. Be sure to give us your findings

 

[PhillyPete]

Will do.

 

[ocguard]

I'm going to piggyback on this thread so as not to start another.

Do the Zone 1 and Zone 2 simulcasts co-exist at all the same sites? That's what it looks like from everything I can find on the FCC ULS. If so, what's the point of this? It seems like an awfully inefficient use of resources, especially since there are several talk groups that are carried by both sites. Just curious why this system is broken into two zones that cover the same geographic area.

 

[HM1529]

I'm going to piggyback on this thread so as not to start another.

Do the Zone 1 and Zone 2 simulcasts co-exist at all the same sites? That's what it looks like from everything I can find on the FCC ULS. If so, what's the point of this? It seems like an awfully inefficient use of resources, especially since there are several talk groups that are carried by both sites. Just curious why this system is broken into two zones that cover the same geographic area.

It's not really that confusing. Zone 1 handles traffic for fire and other city services. Zone 2 handles traffic for the police department. There are only a handful of talkgroups that routinely appear on both zones...the three citywide police talkgroups (J, M, T) and the fire dispatch talkgroups.

 

[ocguard]

It's not really that confusing. Zone 1 handles traffic for fire and other city services. Zone 2 handles traffic for the police department. There are only a handful of talkgroups that routinely appear on both zones...the three citywide police talkgroups (J, M, T) and the fire dispatch talkgroups.

Yep. I get the operations. I'm just curious as to the "why?" Two control channels. Two voice channels theoretically broadcasting the same call from the same towers (for those talk groups that are carried on both zones).

One argument I saw going back through the archives was redundancy. But I'm assuming there's only one core ($$$). Only one backhaul (no microwave equipment is apparent at any of the sites). Also appears each site only has one set of antennas.

Why not just one 35-channel system?