Help with changing control channels

[turnpike61]

I monitor a local system, and they appear to change control channels randomly to just about any active frequency of assignment. Sometimes this happens every few minutes. I don't know the reason for this, but it is annoying.

I have tried two options with my P25RX. I can compile a CC list of every possible frequency assigned to this system, then set the system to enable roaming, with a timeout so that if the CC changes, the system searches for the next CC and then stops there. It's clunky, though, and I can miss calls.

The other option is to disable roaming, and put in a single active CC, then check the boxes for Add Primary/Secondaries/Neighbors. I "think" that will pull in all active CC's and scan across them, so if the CC changes, it will switch, but I still come back to find it's scanning and not stopping.

Anyone else dealing with this, and what is your solution? It may be simple and obvious, but I'm not getting it.

Thanks.

 

[maus92]

I monitor a local system, and they appear to change control channels randomly to just about any active frequency of assignment. Sometimes this happens every few minutes. I don't know the reason for this, but it is annoying.

I have tried two options with my P25RX. I can compile a CC list of every possible frequency assigned to this system, then set the system to enable roaming, with a timeout so that if the CC changes, the system searches for the next CC and then stops there. It's clunky, though, and I can miss calls.

The other option is to disable roaming, and put in a single active CC, then check the boxes for Add Primary/Secondaries/Neighbors. I "think" that will pull in all active CC's and scan across them, so if the CC changes, it will switch, but I still come back to find it's scanning and not stopping.

Anyone else dealing with this, and what is your solution? It may be simple and obvious, but I'm not getting it.

Thanks.

If the cch changes regularly, then the system you are monitoring is likely a Harris system - rotating cch is a feature, not a bug. If it is happening every few minutes, then there is an issue with the system - that would not be normal behavior. Most Harris systems (but not all) are configured to use any system channel as a cch. As for the logic on how the P25RX handles a rotating cch, the Roaming feature is designed to store possible control channels in memory so the radio will roll to next possible cch if the current cch falls below 5 TSBKs per second. So Enable Roaming should be checked, but the the Shuffle feature should be disabled / set to "0."

 

[btt]

The other option is to disable roaming, and put in a single active CC, then check the boxes for Add Primary/Secondaries/Neighbors

This is what I do in order to capture all of the relevant frequencies in the table. After the table is populated, select them and press the "add selected to roaming flash". Once this is done, then enable roaming on the P25RX Config tab. I usually set the number to some high value for the roaming timeout. (like 99999). If the desired control channel is not available for 10 seconds, then the receiver will start scanning through all of the roaming frequencies. The dwell time when scanning is ms (not seconds). The system I monitor never used to change control channel frequencies. Lately, I have observed them testing much more frequently with alternates and secondaries. The method described works well for this.

 

[turnpike61]

Great advice from both of you. Thanks! I was wondering if anyone had advice for some time there