RadioBanter - View Single Post - some help needed with Miami Police frequencies

February 24th 06, 01:32 AM posted to rec.radio.scanner

On 22 Feb 2006 20:15:17 -0800, wrote:

ok. let me re-phrase my question.

If one want to listen to Motorola trunked frequencies, what should
he/she understand about the difference between primary control
channels, alternate control channels and the rest of the channels
(i.e., "black" channels on radioreference.com)? Why should he/she
enter some of them in his/her banks but others not? What do these
channels do for trunking? What is their function/use?

Ok. The system may use any of the primary or secondary control
frequencies at any time. Some switch on a regular basis - hourly,
daily - others use all but one primary as voice frequencies, and
switch one of them to control duty when the normal control transmitter
has a problem.

Now that you understand control frequencies:

You can program all the frequencies - red, blue and black - into your
scanner. Different scanners do things differently, but if you're not
in a "control channel only" mode, if a voice channel gets added, you
have to add it or you miss calls. In control channel only mode, you
only have to program the red and blue frequencies. (Programming the
black ones just wastes scanner memory.) The scanner looks for the
voice channel number on the control frequency, then looks up the
frequency in an internal table and goes to it. If a voice channel is
added the scanner still goes to it, without your having to do
anything.

It's also a lot easier to program 4 control channels than loads of
voice channels.