I am trying to determine a method to isolate communications on a P25 Phase I network's input frequencies from certain entities only, namely fire, police, and medical. I have successfully found which frequencies these are, but cannot find a way to narrow my scanner to only the entities I want to hear.
When setting up a system in Sentinel as a P25 Trunked system the scanner accomplishes this by looking for only certain predefined talkgroup IDs on the trunking control channel, but when a program is set up for monitoring the input frequencies there is no control channel to reference. I was hoping it would scan all the channels anyway, but this wasn't the case.
Instead, I set up a conventional system with every input frequency entered as its own channel. Doing this, I am able to hear every transmission for which I am in range of the original transmitter, regardless of which talkgroup it belongs to. On a conventional system, the only other filter I can see in Sentinel would be the NAC, which seems to be the same regardless of which TGID is transmitting. There is no field to enter a TGID when programming a conventional system.
And with that, I've hit a wall. Does anyone know of a way to separate a certain range of talkgroups from the whole when monitoring trunked channels as conventional ones? I don't care about following the actual conversation or else I'd just scan the repeater outputs as normal; I am doing this to identify when a member of the fire/police/medical services is transmitting close enough for me to be within range of its source. The Close Call feature is not of use to me for this purpose since it will not discriminate TGIDs either, and requires basically line-of-sight to trigger.
If it makes any difference, my scanner is a BCD436HP which is connected to GPS and an external vehicle-mounted antenna.
Thank you!
When setting up a system in Sentinel as a P25 Trunked system the scanner accomplishes this by looking for only certain predefined talkgroup IDs on the trunking control channel, but when a program is set up for monitoring the input frequencies there is no control channel to reference. I was hoping it would scan all the channels anyway, but this wasn't the case.
Instead, I set up a conventional system with every input frequency entered as its own channel. Doing this, I am able to hear every transmission for which I am in range of the original transmitter, regardless of which talkgroup it belongs to. On a conventional system, the only other filter I can see in Sentinel would be the NAC, which seems to be the same regardless of which TGID is transmitting. There is no field to enter a TGID when programming a conventional system.
And with that, I've hit a wall. Does anyone know of a way to separate a certain range of talkgroups from the whole when monitoring trunked channels as conventional ones? I don't care about following the actual conversation or else I'd just scan the repeater outputs as normal; I am doing this to identify when a member of the fire/police/medical services is transmitting close enough for me to be within range of its source. The Close Call feature is not of use to me for this purpose since it will not discriminate TGIDs either, and requires basically line-of-sight to trigger.
If it makes any difference, my scanner is a BCD436HP which is connected to GPS and an external vehicle-mounted antenna.
Thank you!
