In article ,
Andrew Oakley wrote:
....
Then again, I guess the US sees
itself as more of a federation of states rather than one big country,
so maybe you don't see that as odd. Out of interest, does the US have

No, radio broadcasting came into existance at a point where the government
philosophy was much more Federal. (Largely to keep the Navy from running
it all). Radio waves cross state boundries, so regulation is on the
national level. (There are many places where large population centers
are on state boundries).

the RDS system whereby FM radios retune themselves automatically as
you drive around different areas?

Unlike, as I understand it, the UK where you have multiple transmitters
for nationawide and regional "channels" or "programmes" or whatever
you call them, the stucture here is "independent" stations with one
transmitter on one frequency with unique call letters. Programs can
be provided to each station by a network, but most stations are only
a franchise, not owned by the network. (Until about 15-20 years ago
when they allowed large operations to consolidate the industry). So
there was little or no reason to have the radio switch to another
transmitter with the same program, but most likely owned by a competitor.

Does such a system exist for AM when
you drive really long distances? In the UK that obviously isn't a
requirement... ;-)

At night time, there are the clear channel stations, with maximum
power (50 kW) and only one or two stations on that frequency in the
country.

Now there are the two satellite operations, XM and Sirius, running
in the 1.5? GHz band.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)