Guessing they are just resource groups if there is a mass casualty accident so they can patch in outside agencies assisting in the response.
Not exactly. Harris EDACS and P25 radios systems maintain a pool of talkgroups that are automatically assigned by the system for the purpose of patching multiple different talkgroups on the same system together. These talkgroups are dedicated for intrasystem patching.
DIA uses them mostly for simulcasting warnings and alerts to public safety and airport staff.
In a large incident, outside agencies responding to DIA would most likely use the mutual aid talkgroups that are linked to other systems, or use the DIA system directly. It is possible to further complicate this by patching a DIA talkgroup with any of the mutual aid talkgroups, which would then end up on a System Assigned ID (SAID) talkgroup.
My understanding is talkgroups are not scanned so removing the "SAID" patches talkgroups would not make any difference in speed.
Shawn is correct. The number of talkgroups has no effect on how fast a scanner scans trunked system. A scanner needs to spend a set amount of time on a control channel for a trunked radio system to find out what talkgroups are active. The programmed talkgroup determines if the scanner will attempt to monitor that talkgroup and what it will display.
Locking out those talkgroups probably does not matter as much on the Whistler scanners. They should be able to recognize and follow the talkgroup patching that uses the SAID talkgroups as long as you have one of the talkgroups being patched programmed. It is not advised on Uniden scanners since they do not have the ability to track patching on P25, so any sort of transmission made during talkgroup patching will be lost to the abyss.
