Talk Group Patching

[Bill28227]

I have a Pro-95 and listen to a Motorola Type 2 system. The City often patches TGs together such as Baker-1 and Baker-3. A policeman's walkie talkie will get the same traffic on both TGs because it is patched. But on my scanner I will hear the traffic on one of the two TGs. Why is that and can anything be done to my Pro-95 or other scanners to get the traffic on both TG ids? I have done searches many times and the traffic is only going out on one TG. Thanks for any insight!

 

[mikey60]

When talkgroups are patched, one of the patched talkgroups become a "supergroup". A message is transmitted over the control channel telling all radios that are on any of the patched talkgroups to use the supergroup.

As an example, Talkgroup 16 is patched into talkgroup 32. In this case talkgroup 32 becomes the "supergroup" and all radios that are set to use either talkgroup will use talkgroup 32. You will hear no traffic on talkgroup 16 while the patch is in place.

Mike

 

[Bill28227]

Thank you for the logical reply. I knew that there were not two or more frequencies of the same radio traffic being used but never thought about the super talkgroup idea. Too bad our scanners can not also decode that info.

 

[mikey60]

All the scanner looks for is the channel grant or grant updates, and displays that talkgroup. They don't show when a patch is present, at least not the current versions.

Mike

 

[mam1081]

The BC780 will show patches in EDACS systems - I have had mine beep and flash patchID, display all of the TGIDs that were patched, and listened to the audio from the "Supergroup". I have never had it happen on a moto system, so I think it just stops on one of the groups, like you said.