Thanks for all the good help.

I believe, now I understand .


"Curtis CCR" wrote in message
om...
"Scott Downey" wrote in message
...
sure, the duplex channels are separated so each person transmitting does
not
step on the other persons transmission, therefore both could talk and be
heard if you had 2 radios or a special radio where you could hear and
talk
at the same time.

But if you have 2 boaters both on the same duplex channel talking to one
shore station on its own complemntary channel, each boater should be
part of
the same conversation. There would be no difference between them as they
would both be using the same duplex channel. So therefore another boater
ought to be able to listen in if tuned to the same duplex channel that
the
other boater was using talking to the shore station.

Yeah. You can listen in on the transmissions from the shore station,
not the other boats.

If two boats are talking to a shore station on, say, channel 84. both
of the boats will only hear the shore station, not eachother.

Think off a tin can telephone system. With one string (frequency) you
are simplex. In theory you can't hear the other guy talking when you
are talking because you have the can to your mouth instead of your
ear. Only one person can talk at a time, but only one string is
needed for a two-way comm.

With duplex there are two strings (frequencies). The string from your
transmitter is connected to shore station's receiver. That string
only goes one way. The other string goes from the shore station's
transmitter to your receiver. Again it's only one way on each string.

The other boats' strings are set up the same way. The only way to
hear other boats would be to swap the strings on your radio. You
can't do that.

Does anyone sell a special radio that allows one to hear and talk at the
same time? I dont see that in the catalogs. Using 2 radios is a work
around,
I suppose.

The only thing that would allow is for you to transmit and receive
simultaneously (full duplex as opposed to half duplex). It will not
change the frequency set and allow you to talk to other boats on a
duplex channel.