Question regarding Galveston and TDMA

[Tim-in-TX]

Okay, so I was looking through the TxWarn P25 database and noticed that there are a handfull of talkgroups that have "T" (TDMA capable talkgroup) listed under the Mode column. For example:
265 - T - Galv PD2 Alt - Police Ch. 2 Alternate
3267 - T - Galv PD3 C-C - Police Ch. 3 Car-to-Car
3185 - T - GalvBchPtrl1 - Beach Patrol 1

But none of the Houston Public Safety towers cover the island, much less even reach it. Even the Santa Fe tower only reaches as far as Hitchcock.

Are they just noting that the systems are capable of TDMA, but they may not be currently using it...or at least not until they get a tower that will cover the area?

 

[Tim-in-TX]

Wow, two days, 123 views, and no answer...my question must have been so dumb it wasn't worth the time. LOL! I didn't even get the "USE THE SEARCH!", or "READ THE WIKI" type answers.

 

[nd5y]

As far as I know the whole TxWARN P25 system is capable of phase II TDMA.
The database shows there are 8 sites in Galveston county.
What you posted does not make sense. What exactly do you want to know?

 

[motorola_otaku]

TDMA is not exclusive to the Zone 3 (Houston) sites. Sites on Zones 1 and 2 have TDMA-capable channels.

To answer your question, Galveston city public safety largely operates in dynamic mixed mode, meaning their talkgroups could be operating in FDMA or TDMA depending on what models of radio are affiliated. Many other agencies on Zone 1 sites operate this way, and some are TDMA-exclusive. It depends largely on what kind of radio fleet they have (or what their budget for new radios is.)

Realistically anyone scanning the Houston/Galveston region should be using TDMA-capable equipment, regardless of location or target agency.

 

[Tim-in-TX]

TDMA is not exclusive to the Zone 3 (Houston) sites. Sites on Zones 1 and 2 have TDMA-capable channels.

To answer your question, Galveston city public safety largely operates in dynamic mixed mode, meaning their talkgroups could be operating in FDMA or TDMA depending on what models of radio are affiliated. Many other agencies on Zone 1 sites operate this way, and some are TDMA-exclusive. It depends largely on what kind of radio fleet they have (or what their budget for new radios is.)

Realistically anyone scanning the Houston/Galveston region should be using TDMA-capable equipment, regardless of location or target agency.

Okay, I was operating under the impression that, in order to receive a TDMA transmission, only one of the Zone 3 sites could be used. Thanks for the clarification. It seems like the older I get, the harder it is to wrap my head around these modern systems.

 

[KG1ADP]

The League City Tower in Galveston County has Phase II enabled which means if there is a TDMA capable radio that is affiliated with that tower the talkgroup it is on is TDMA. The Site is dual modulation FDMA and TDMA.

 

[PlanoTX]

The League City Tower in Galveston County has Phase II enabled which means if there is a TDMA capable radio that is affiliated with that tower the talkgroup it is on is TDMA. The Site is dual modulation FDMA and TDMA.

With Motorola dual dynamic mode (DDR) if one radio is affiliated to a talk group (and all other radios are phase 2), the talk group will revert to phase 1. The system always reverts to the lowest common denominator or phase 1 so that every radio hears the transmission. The system cannot broadcast phase 1 and phase 2 traffic on the same rf channel. The system can be set to ignore Phase 1 radios, but then it is not DDR. I have seen other (brand X) systems use 2 rf channels when it sees both Phase 1 and Phase 2 radios on a single talkgroup (one RF channel for Phase 1 traffic and one RF channel for Phase 2 traffic), but Motorola DDR does not do that.