I think you have the gist of it, Wayne. This feature does NOT
program any channels for you. What you have to do is to program
into the bank all of the frequencies which can be control
channels. This way you won't have to mess with it after the
initial setup. As the control channel moves around, the 780 will
be able to tell which of the N frequencies is the control channel
and just park on it.In a way, this feature sounds like the best thing since sliced
bread but it isn't cracked up to be all you expect. You can't
just surf the airwaves to find a control frequency, plug in and
turn on this mode. Why? First off, you have the problem of the
rotating control channel mentioned above. If this is the only
frequency you know of in the system, when the system changes to
another frequency for the control channel you have no idea of
what it is so your monitoring is at an end for this system.
Secondly, when turning on this feature, you also have to tell it
which of 4 plans to map the system frequencies to. The only way
to successfully do this is to know all of the frequencies in
the system so you can use the rules in the operating guide to
select the proper plan of the 4. Well, if you know all of the
frequencies in the system I guess you don't need the control
channel mode to tell you what they are! The other methodology
would be to select each of the 4 plans in turn and spend some
time monitoring the system traffic. If you get missed replies
or can tell you're getting traffic from another system (which
isn't easy to do since trunked systems have users from janitors
to building inspectors to police to EMS to social workers to
park personnel...), then you know it's time to move on to the
next plan to see how it works.
Now, here's how I've been using it (besides testing it on a known
system to see that it works properly). There is a relatively new
Mot system in the area which, if you look it up by call sign, is
composed of 33 frequencies. Since it has more than the max of 29
trunked systems are supposed to have, this must be some kind of
spliced system with two or more distinct systems patched
together. So what I did was to punch in one of the control
channels and I can now see the frequencies that involved for
the traffic on that system. This should help me pick out the
right frequencies for one of the systems which will hopefully
end up being just a subset of the 33 frequencies.
The other thing this feature is good for is as a lazy man's
method of programming. Simply program in the few control
channels frequencies without having to enter all the voice
frequencies and you're good to go!