Lets talk about the 10kc switch on most of your newer radios.
First a brief history on the older 23 channel radios.
Actually all 23 channel radios were 28 channel radios
and 40 channel radios are 45 channel radios.
These add'l 5 channels were actually blocked out via the
channel selector.

All CB channels are 10kc apart i.e. channel 1 is 26.965mhz,
channel 2 is 26.975mhz, and channel 3 is 26.985,
and channel 4 is 27.005mhz.  If you look at channel 3 and
channel 4 you will notice they are 20kc apart.
What just happened here?
Take channel 3 @ 26.985 and add the 10kc you get
26.995mhz or what some people refer to as channel 3A.
So we conclude there are 5 "A" channels.
Channel 3A- 26.995
Channel 7A- 27.045
Channel 11A-27.095
Channel 15A-27.145
Channel 19A-27.195
This hold true for the 40 channel radios as well
and most exports as well.

The "A" channels are not used very much because
I believe most people don't know about them.
Weather there legal, to use, or not is not up to us
to determine here but people do use them.

We tried to find out what the "A" channels were designed for
and came up with a possibility they were used primarily
for Model Boats, Model Airplanes, and Garage Door Openers.

If any of you can shed more light on this subject Please
let us know.