curious about control channels

[Ronnierozier2]

How does one go about finding control channels for a site? im new to all this and recently bought me a SDS100 scanner radio

question. One a site close to me i have 3 control channels and 2 other frequencies for the site. the first 3 are labeled as control channels. I notice when i log with Proscan im hearing traffic on other frequencies. do the control channels point my scanner to other frequencies that they are talking on? im trying to figure all this out. I'm in Mississippi monitoring MSWIN. its a P25 Phase II to my knowledge

 

[tvengr]

All of the frequency information is carried on the control channel. That is why you only need to program the control channel and alternates.

 

[dlwtrunked]

How does one go about finding control channels for a site? im new to all this and recently bought me a SDS100 scanner radio

question. One a site close to me i have 3 control channels and 2 other frequencies for the site. the first 3 are labeled as control channels. I notice when i log with Proscan im hearing traffic on other frequencies. do the control channels point my scanner to other frequencies that they are talking on? im trying to figure all this out. I'm in Mississippi monitoring MSWIN. its a P25 Phase II to my knowledge

Lets be clear. There is only one control channel in actual use at a time. The control channel will rotate over time between you possible 3 control channels. When the other 2 of those 3 are not control channels then they join the other two as being used for voice communication. Yes, the control channel tells what talkgroup is using what frequency (think of talk groups as being places like virtual channels for agencies and sub-agencies to talk). Generally, you once you put frequencies in a scanner, it will find the active control channel and use it. Generally you also have to tell a scanner what talkgroups you are interested in and it will ignore the others. In many scanners, you can just enter all the frequencies and it will find what the active control channel is (in other words you do not have to identify which subsets are control channels in them.)

 

[ofd8001]

A little more on the above. . .

There is no harm in programming all of the frequencies associated with a site. On older model scanners (those without an SD card), memory was a little more limited, so control channel only programming was a good thing.

If you select only those sites close to your location (about 30 miles or so), there is no detriment to scanning speed. (It is a big waste of scanning resources to monitor all sites associated with a large, statewide system, which I am assuming you are monitoring.)

 

[GTR8000]

There is no harm in programming all of the frequencies associated with a site.

That is no longer 100% true. Read this thread for the reason...

SDS100/SDS200: - Not finding CC

This may happen to the SDS200 also as well as others models, but I've confirmed it on my SDS100. Randomly I turn my SDS100 on and it will show it's sitting on a frequency and will show "DATA", but the system ID, site number and RFSS are blank and it won't receive any calls. Today I confirmed it...

forums.radioreference.com

 

[ofd8001]

You are quite right. Since I've not monitored a system that is doing data on a TRS, I still program all frequencies. Should I encounter that issue, I would probably do control channel only. I'm sure the database would indicate if there is data being transmitted on the system channel.

 

[GTR8000]

I'm sure the database would indicate if there is data being transmitted on the system channel.

There is no indication in the database as to whether a system carries data in addition to voice. It's an issue that Uniden really needs to address.

 

[W4KRR]

On Harris systems, any channel can be used as the control channel, so you would need to program all frequencies if it's a Harris system.