Questions about GATRRS/Austin P25

[garys]

On my last trip there in November, I was hearing them better on Simulcast 1, but I was in Northwest Austin off of Research. I was using a 436HP at the time, so found that Avoiding Simulcast 2 worked better. I don't know how different that will be with SDS100 if you use that.

IR is an "IntelliRepeater" used to fill in dead spots in the system. Unless you are in the dead spot area, there isn't much reason to listen to them. I don't know for sure about P25 systems, but I know that on analog Motorola systems you only hear traffic on an IR if there is a unit affiliated with the site. You only hear the Talk Group that individual radios are using, not all of the traffic.

As I recall, the 700Mhz site down town is only used by units in and near the Capital building. I've never heard anything on it during my various trips there.

 

[rbarker]

Most all public safety (Police, fire, EMS, sheriff and DPS are on Simulcast 1. Simulcast 2 is mostly public works. The 700 Mhz tower is strictly for The capitol building DPS. For officers that patrol other state office buildings and traffic stops around the capitol are also on Simulcast 1.
The IR Intellirepeaters are only used on rural area to fill in gaps.

 

[rbarker]

Most all public safety (Law, EMS, Fire) is on Simulcast 1; whereas Simulcast 2 is public works, but they can always overlap. The IR intellirepeater sites are fill in sites in fringe areas.

 

[Project25_MASTR]

IR is an "IntelliRepeater" used to fill in dead spots in the system. Unless you are in the dead spot area, there isn't much reason to listen to them. I don't know for sure about P25 systems, but I know that on analog Motorola systems you only hear traffic on an IR if there is a unit affiliated with the site. You only hear the Talk Group that individual radios are using, not all of the traffic.

IntelliRepeaters aren't P25...technically. City of Austin uses the term IR Site to define sites which are not simulcast but still make up core city sites. Originally, they may not have been part of the P25 trunking system but their own self contained SmartNet sites. Intellerepeaters were Motorola Quantar's with special SCMs. All of the trunking logic was built into the SCM so there was no need for site controllers (you had to have a zone controller if you wanted to have multi-site trunking). The cool bit about IRs that no one ever really utilized, they could be used as a single channel trunking site. Anyway, Astro 25 (Motorola's P25 trade name) has always required external controllers interfaced to Quantars (and later GTR800s).

The sites are standard P25 trunking sites (not simulcast but still linked to the rest of the trunking system). They are no different (other than band) than the sites that make up Western Counties, Middle Rio Grande, and Permian Basin on VHF. City of Austin refers to them as a legacy SmartNet site.

Today the equivalent would be an Astro 25 Express site...which is a GTR8000 ESS with two controllers, however many repeaters needed, and no zone controller which means the site is always advertising "Site Trunking" and the system is effectively open to any radio that attempts to register/affiliate. Two examples of Express sites are City of Woodway and Lacey Lakeview...which most users have abandoned in place and migrated to Heart of Texas. You could also classify the 902 System in Dallas as an Astro 25 Express but it is actually made up of Quantar's and not GTRs (same concept though but never a actually sold as a solution like the Express). Concho Valley COG's system is technically an arrangement of Express sites since it was never finished by interconnecting sites and setting up a Zone Controller.

TLDR: City of Austin uses a term that actually refers to older SmartNet systems to reference their non-simulcast sites. It's standard P25 wide-area trunking site and no different from the VHF sites in the system.

 

[KevinC]

Today the equivalent would be an Astro 25 Express site...which is a GTR8000 ESS with two controllers, however many repeaters needed, and no zone controller which means the site is always advertising "Site Trunking" and the system is effectively open to any radio that attempts to register/affiliate. Two examples of Express sites are City of Woodway and Lacey Lakeview...which most users have abandoned in place and migrated to Heart of Texas. You could also classify the 902 System in Dallas as an Astro 25 Express but it is actually made up of Quantar's and not GTRs (same concept though but never a actually sold as a solution like the Express). Concho Valley COG's system is technically an arrangement of Express sites since it was never finished by interconnecting sites and setting up a Zone Controller.

Since you brought it up...if you set a site as "ASTRO Express" in the site controllers it won't advertise itself as being in site trunking. And you can, to a certain extent, limit TG's and radio ID's via the "Sub Band" restrictions (of which you can have 128 ranges for TG and 128 for radio ID's).

 

[Project25_MASTR]

Since you brought it up...if you set a site as "ASTRO Express" in the site controllers it won't advertise itself as being in site trunking. And you can, to a certain extent, limit TG's and radio ID's via the "Sub Band" restrictions (of which you can have 128 ranges for TG and 128 for radio ID's).

That's very interesting...as the Woodway system at least was sold as an Astro 25 Express site, staged by Motorola and has always advertised Site Trunking.

 

[KevinC]

That's very interesting...as the Woodway system at least was sold as an Astro 25 Express site, staged by Motorola and has always advertised Site Trunking.

Your first mistake was trusting CCSI.

ETA...
It's also very possible it got changed in the field.

 

[garys]

"Kleenex."

IntelliRepeaters aren't P25...technically. City of Austin uses the term IR Site to define sites which are not simulcast but still make up core city sites. Originally, they may not have been part of the P25 trunking system but their own self contained SmartNet sites. Intellerepeaters were Motorola Quantar's with special SCMs. All of the trunking logic was built into the SCM so there was no need for site controllers (you had to have a zone controller if you wanted to have multi-site trunking). The cool bit about IRs that no one ever really utilized, they could be used as a single channel trunking site. Anyway, Astro 25 (Motorola's P25 trade name) has always required external controllers interfaced to Quantars (and later GTR800s).

The sites are standard P25 trunking sites (not simulcast but still linked to the rest of the trunking system). They are no different (other than band) than the sites that make up Western Counties, Middle Rio Grande, and Permian Basin on VHF. City of Austin refers to them as a legacy SmartNet site.

Today the equivalent would be an Astro 25 Express site...which is a GTR8000 ESS with two controllers, however many repeaters needed, and no zone controller which means the site is always advertising "Site Trunking" and the system is effectively open to any radio that attempts to register/affiliate. Two examples of Express sites are City of Woodway and Lacey Lakeview...which most users have abandoned in place and migrated to Heart of Texas. You could also classify the 902 System in Dallas as an Astro 25 Express but it is actually made up of Quantar's and not GTRs (same concept though but never a actually sold as a solution like the Express). Concho Valley COG's system is technically an arrangement of Express sites since it was never finished by interconnecting sites and setting up a Zone Controller.

TLDR: City of Austin uses a term that actually refers to older SmartNet systems to reference their non-simulcast sites. It's standard P25 wide-area trunking site and no different from the VHF sites in the system.