"Chuck Tribolet" wrote in message ...
There's a US/International mode on radios not because the channels
have different USES, but because they have different FREQUENCIES.
For example, international Ch 22 is a full duplex channel on 157.100/161.700
while US 22A is a simplex channel on 157.100.

I think that over time the marine telephone channels will be freed for other
uses.

Yes - they are simplex in the US and duplex on international...
because they have different uses. 22A in the US is a Coast Guard
"liason" channel that you can use to talk to the CG ship-to-ship
(talking to a CG vessel) or ship-to-shore (talking to a CG station).

In in other parts of the world 22 (the duplex channel) is used for
port operations.

Not to say that 22A is not used outside the US. Doesn't Canada use
22A for the same thing we do?


"Curtis CCR" wrote in message om...

How marine channels are used is a international issue. In many parts
of the world these duplex channels are still used more than they are
in the US. There are a couple of channels that have different uses in
the U.S. than in the rest of the world. This is why you have a
International / U.S. mode on your set. When foriegn vessels enter
U.S. waters they want to be able to use their "international" radios.
Likewise, if you take your boat to another country, you may want to be
able to contact a coast station on one of those international
channels.