I've been kind of busy with work so sorry for the late reply.
Chip Johnson writes:
>     In the US, as I recall, it's 150 miles. I used to operate on 11
> meters and always wondered why, if we weren't supposed to talk over 150
> miles, we were allocated a group of frequencies where it was quite easy
> to do so a good deal of the time. Guess that's government for ya.

Well, not really. It's technology and government's attempts to
make the best of a not so good situation.

	CB in the United States started in 1958 after about ten
years of planning. Keep in mind that about ten years means 1948.

	The idea was to have a low-cost low-power radio service
for private citizens to use for personal communications or small
business applications. Oh yes and it would be nice if they
actually worked.

	What became the CB frequencies was about the highest
frequency one could build consumer radio gear that would
transmit and receive efficiently enough to barely qualify as
useful.

	There was an article in "Popular Electronics" around
1965 or so that described the history of CB in the United States
and it may have included the words "Big Brash Band," but I may
also be mistaken.

	There were some pilot projects across the US in the
early to mid fifties but 26.965 to 27.something was still the
Eleven-meter ham band for most people. It also had something
else on it that made it undesirable for hams. It had ISM or
Industrial Scientific and Medical frequencies in it. Those are
usually heaters for drying lumber or other industrial heating
applications plus medical diathermy gear such as what your
doctor might connect to a sore muscle in your back or leg. These
were bad-boy transmitters that had no filtered power supplies
and either ran straight AC on the plates of their tubes or used
a half-wave rectifier so what you heard was a drifty loud buzz
at 60 HZ in North America or 50 HZ from some parts of South
America and most of the rest of the world.

	Eleven meters was a waste land full of a few hams and
lots of diathermy which is why we lost it as a ham band.

	An old-timer told me that there were a different class
of CB channels in the UHF range around 450 MHZ and they were
absolutely useless. No output power and regenerative receivers.

	My own personal opinion is that eleven-meter CB should
go away and the band returned to amateur use all over the world.
We can make use of the skip and do so legally. Commercial uses
of those frequencies would be hampered by the variable
propagation characteristics.

	The FRS radios in the 462 and 467 MHZ ranges are exactly
the kind of low-cost communications that were envisioned in the
forties and the lack of skip means much more consistent
operation.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Telecommunications Services Group