Old Sarpy system changed the control channel 859.9875

[scanomaha]

I noticed yesterday that the old Sarpy County (Motorola) system changed their control channel to
859.9875
https://www.radioreference.com/apps/db/?sid=622

 

[NebraskaCoder]

It's been moving control channels for awhile now. I read somewhere that's how the system is designed.

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[kruser]

The old Smartzone sites around here are setup to rotate the CC about midnight each night. I think this is the default behavior of a SmartZone system as NebraskaCoder indicated. I have seen a SmartZone site here that kept the same CC though so I guess this can be changed by the sysadmin for the system.

We also have Harris P25 Phase I systems (several sites used by our power utility) that rotate their CC also about midnight each evening. The Harris systems also don't broadcast any Alternate CCs over the current control channel when you watch the data with Pro96com. Usually I've found that any frequency used by each site can become the CC for the day.

This can make monitoring these sites in conventional mode a pain as you must unlock yesterday's CC and lock out the new ones if using a communications receiver that cannot trunk track and also mute the CC data signal.
The newer Icom R30 and R8600s will both pause briefly on the active CC so you don't really need to lock them out but most comm receivers don't offer this luxury.

 

[kayn1n32008]

The old Smartzone sites around here are setup to rotate the CC about midnight each night. I think this is the default behavior of a SmartZone system as NebraskaCoder indicated. I have seen a SmartZone site here that kept the same CC though so I guess this can be changed by the sysadmin for the system.

We also have Harris P25 Phase I systems (several sites used by our power utility) that rotate their CC also about midnight each evening. The Harris systems also don't broadcast any Alternate CCs over the current control channel when you watch the data with Pro96com. Usually I've found that any frequency used by each site can become the CC for the day.

This can make monitoring these sites in conventional mode a pain as you must unlock yesterday's CC and lock out the new ones if using a communications receiver that cannot trunk track and also mute the CC data signal.
The newer Icom R30 and R8600s will both pause briefly on the active CC so you don't really need to lock them out but most comm receivers don't offer this luxury.

Motorola Type 2 and P25 use 4 channels as the control channel and alternate control channel. Harris can use any channel as the control channel


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[kruser]

Motorola Type 2 and P25 use 4 channels as the control channel and alternate control channel. Harris can use any channel as the control channel


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I see that as true except in the case of VHF P25 Motorola sites which only have 5 frequencies total in many of the cases for our statewide system. The current CC will only advertise one Alternate CC.
I'd guess there must be a minimum amount of available frequencies assigned to a P25 site before they will show 1 active CC and 3 alternates?

All the SmartZone or Type 2 sites still on the air here do have 10 or more frequencies so they will advertise all 4 that can be CCs.

 

[scanomaha]

I been listening to this system https://www.radioreference.com/apps/db/?sid=622
daily for about two years....and up until real recent...they been operating on just one
primary control channel 854.5375...and only one alternate 859.2375

but like i said above.... just the other day, they dipped into the reg pool of frequencies and now are operating on 859.9875 as the control channel.... in the past two years, they never have rotated the control channels.... this is a ten freq system.... and i assume because they are rolling out a completely new P25 system it had something to do with the change.