Rotating CCs

BaLa · #1 (**permalink**) 10-05-2007, 08:49 PM

I just got to thinking about this.

What exactly is the purpose of rotating control channels in a trunking system ?

mancow · #2 (**permalink**) 10-05-2007, 08:56 PM

It's to save on wear and tear on the transmitters.

BaLa · #3 (**permalink**) 10-05-2007, 09:03 PM

Quote:

Originally Posted by mancow

It's to save on wear and tear on the transmitters.

That's it?
Simple enough, lol..

mancow · #4 (**permalink**) 10-05-2007, 09:05 PM

I'm not sure if Motorola systems do this but I know EDACS systems have self diagnostic monitor systems in place that check the quality of the channel the control is operating on. If it's not acceptable the system will automatically rotate to another channel and if it's too bad it will drop it from use until it's fixed.

W0JJK · #5 (**permalink**) 10-06-2007, 12:01 AM

A Motorola system will roll to another control channel if it thinks there is a problem with the current channel. There is four available control channels.

On the note to save the transmitter, I have seen more PA go out on the channels that heat up and cool down more often than the channels that are always being used like the control channel.

mancow · #6 (**permalink**) 10-06-2007, 03:14 AM

It would make sense, sort of like a light that gets turned off and on a-lot.

fineshot1 · #7 (**permalink**) 10-06-2007, 12:49 PM

For the moto trunk systems - In the early days of trunking the pa's were not as robust as they are now so about every 12 or 24 hours(it was a user definable parameter) the controllers would rotate the control channel(there were usually 4 but not on every system). If there is an illegal carrier on the inbound control channel that will also cause a shift in control channel. These days the pa's are very robust and rotation is not usually done much anymore as a standard system practice but again this depends on the system.

wayne_h · #8 (**permalink**) 10-08-2007, 01:45 AM

The old controllers (6809 platform) are defaulted to rotating to each available control channel; that's depending on certain conditions like preferred tagging which can prevent it. The newer systems (SmartZone for example, or those that use the MTC3600 controller) do not do this. The stations in the newer system types are rated for continuous duty and don't need it.

flecom · #9 (**permalink**) 10-17-2007, 07:53 PM

i know that on most 800mhz edacs systems have test radios that monitor each channel, if one has an issue it will disable it... control channels also move if they detect a foreign carrier on that frequency...

KS4VT · #10 (**permalink**) 10-18-2007, 08:56 PM

Motorola does that also. If it sees an "illegal carrier" for the length of time determined by the System Admin it will take that channel out of service system-wide. If the control channel sees the same it rolls to the next one in line.

An issue with an illegal carrier on an active control channel is that field users who have a lower signal level than the interference will get bonked until the interference clears or the channel changes.