Control channel switch

[N5MRK]

The night of the ScanOKC meeting, Matthew and I came back to my apartment to complete the data slicer. We had it all built and were testing it. We had some problems so it was taking a while. We had set the scanner to monitor the control channel of edmond. it was on hold. So we were testing away and at 12:00 exactly, the control channel went dead. I was like wtf.... lol. So i hit scan and it picked it up on one of the other frequencies.

So i guess my question has two parts. One, why in the world would they do that? And two, if they do that, is it every night? Or random?

Anyways, thanks for the info.

-Matt

 

[robynsjw]

Edmond's control channel seems to always change at 12 midnight. (Noticed that before I got the trunktracker) Sometimes I've noticed it change at 12 noon, but I don't think that is everyday. It also seems to change during thunderstorms, I assume the power surges cause that.
I also always assumed they all did that so that one TXer wouldn't be on 100% of the time, give them all some "time off".

 

[foster_006]

Edmond's control channel seems to always change at 12 midnight. (Noticed that before I got the trunktracker) Sometimes I've noticed it change at 12 noon, but I don't think that is everyday. It also seems to change during thunderstorms, I assume the power surges cause that.
I also always assumed they all did that so that one TXer wouldn't be on 100% of the time, give them all some "time off".

OHP's CC never changes. Although I did notice that Edmond's does.

When I lived in Joplin, they changed the CC every night. Someone there told me the reason why they do that, but I have since forgot!

 

[fast2okc]

There are two schools of thought on switching control channels on Motorola systems. Some feel rotating the control channel will make the equipment last longer. Others feel leaving the control channel on a single channel is better.

Edmond, Shawnee and Norman switch control channels every night. The DPS sites use the same channel all the time. Haven't known any DPS system failures due to the control channel. Do the Tulsa control channels switch?

I guess it's like turning your computer or monitor off when you are not using them. You can find experts to argue both sides.

--FAST 2

 

[mam1081]

I externsively monitored and tracked a systems' data channel switching over about 6 months. It would change every day at almost exactly (plus or minus about 10 seconds) the same time. It would go in order from lowest to highest frequency unless someone was talking on that one - then it would skip that and goto the next in line. The radios automatically switch. I never confirmed it, but sometimes my scanner would pick up an odd talkgroup right before it switched. I don't think the trunked system tells radios it is about to change, but it might. Trunking radios (motorola only here) only have the control channels programmed in them - none of the voice channels are programmed in the radio itself, so scanning for a new CC shouldn't take too long at all.

The OKC site of the OK State SZ system does change data channels - not very often at all though. There is an "alternate channel" listed on the DB, and I have seen it on there a few times. FYI, smartzone and other networked systems tell the radios what the surrounding cell site data channel frequencies are also.

 

[GlacierClipper]

Tulsa does switch control channels from time to time.

860.9375, 859.9375 and 858.9375. Used the most.