When will GATRRS turn on TDMA?

[Unitrunker2]

Danger - this post contains speculation.

So, does anyone know when GATRRS will turn on Phase 2? Like maybe this July?

Site 7 represented a significant upgrade that I believe includes TDMA capability. Most everone has APXs, so I doubt many non-TDMA capable subscriber units remain. Sites 7 and 20 spew out two slot TDMA identifier updates.

Anyone care to spill the beans?

When this does happen, you'll see new channels with an LCN prefix of 5 (for 770 MHz) or 6 (851 MHz).

 

[Project25_MASTR]

You might want to check your bandplan again on the OTA data. It was advertising the two 7/800 TDMA channel IDs in addition to six VHF TDMA channel IDs back in December. It's been advertising the 7/800 channels for several years now though.

The Travis County simulcast will not gain anything from going TDMA. Reason being for this is that Travis County is fully built out on FDMA with 30 channels. Motorola has a limitation of 28 or 29 simultaneous talk paths (regardless of FDMA/TDMA). So turning TDMA on in that case won't actually provide additional capacity other than allowing a call from elsewhere in the zone to remain TDMA if it is originating as TDMA.

You will see TDMA pop up in the MRG region first. Maybe as soon as this summer. There are still thousands of Phase 1 only radios on GATRRS (including APXs). Relatively speaking, the region that would benefit the most from TDMA is MRG. Everyone else for the most part doesn't really need to force a TDMA migration.

 

[Echo4Thirty]

Motorola has a limitation of 28 or 29 simultaneous talk paths (regardless of FDMA/TDMA). So turning TDMA on in that case won't actually provide additional capacity other than allowing a call from elsewhere in the zone to remain TDMA if it is originating as TDMA.

I thought this was addresed in a system release to provide more talkpaths?

 

[Project25_MASTR]

I've been informed that now you can do at least 36 talk paths (as evident on NTIRN) so my previous statement may be somewhat incorrect depending on the release version the City of Austin is running and when that feature was introduced. That being said, it's pretty much a business decision. Does the amount of busies/call loading justify forcing a Phase 2 migration and the added costs associated with that or is it manageable as is?

I can actually speak for a fact though...cost has been a major factor in purchasing radios outside of Travis County and in my experience Phase 2 being optioned in APX radios had less than a 50% uptake, especially in the rural counties and now that flash options can no longer be ordered to upgrade a lot of those APXs to Phase 2...you are looking at once again buying new radios just to support a complete Phase 2 migration.

 

[kmartin]

A lot of you might think this is incorrect , but I get the feeling that in the future a majority of public safety trunk systems will make the adjustment to a complete phase 2 system or fully encrypted system , so monitoring them will be difficult if not impossible
This is why I haven't invested in the SDS scanner

 

[Project25_MASTR]

A lot of you might think this is incorrect , but I get the feeling that in the future a majority of public safety trunk systems will make the adjustment to a complete phase 2 system or fully encrypted system , so monitoring them will be difficult if not impossible
This is why I haven't invested in the SDS scanner

No issues monitoring Phase 2. Its where encryption is invovled that it is going to affect the normal users. Luckily many counties just aren't that interested in using encryption.

 

[Unitrunker2]

I've been informed that now you can do at least 36 talk paths (as evident on NTIRN) so my previous statement may be somewhat incorrect depending on the release version the City of Austin is running and when that feature was introduced.

Thanks for that detail. I remember site 1-1 and 1-2 had about 50 channels combined. Replacing them with site 1-7 and 30 channels made me wonder about capacity.

 

[Project25_MASTR]

Thanks for that detail. I remember site 1-1 and 1-2 had about 50 channels combined. Replacing them with site 1-7 and 30 channels made me wonder about capacity.

I will say, unlike some of the dual layer sites at NTIRN the original County Wide and E620 layers had some co-located sites but overall the two layers provided different coverage footprints. The current system not only consolidated County Wide and E620 but also eliminated the the Singleton Bend, Creedmoor, Honeycomb, and other "IR" sites and rolled them in as part of the simulcast.

 

[kmartin]

No issues monitoring Phase 2. Its where encryption is invovled that it is going to affect the normal users. Luckily many counties just aren't that interested in using encryption.

I guess what I meant is a pure phase 2 system that uses a phase 2 control channel. I don't think the SDS will monitor that I think only the computer generated software can do those I'm thinking that public safety systems might start bringing these types to life in the future and thinking uniden may need to manufacture a scanner that can monitor a pure phase 2 system if this happens

 

[Echo4Thirty]

The only vendor currently supporting TDMA control channel is Harris so until other vendors support it on their subscribers, I don't see it widely deployed.

Keep in mind that control channel encryption could also come about one day but I don't see it anytime soon on mixed vendor systems.

 

[mwjones]

I guess what I meant is a pure phase 2 system that uses a phase 2 control channel. I don't think the SDS will monitor that I think only the computer generated software can do those I'm thinking that public safety systems might start bringing these types to life in the future and thinking uniden may need to manufacture a scanner that can monitor a pure phase 2 system if this happens

You are correct, the SDS scanners currently will not decode a Phase 2/TDMA Control Channel. Fortunately, the only place I've seen it is on American Electric Power (AEP) in Northeast Texas and Oklahoma, and more recently on a single site of the new Dallas Area Rapid Transit (DART) System.