On Dec 1, 2:37 am, "Al Gillis" wrote:
I'm guessing the OP intended to type selcal. If so, that stands for
Selective Calling, a scheme where two audio tones sent before a conversation
starts "unlock" the receiver's squelch so the conversation can be heard.
Other radios on the frequency which receive those tones (the SelCal "code")
don't unlock and the conversation is unheard. I've heard SelCal used when
aircraft control stations are calling trans-Pacific commercial aircraft.http://en.wikipedia.org/wiki/Selective_callingprovides a pretty good
explanation.

Al

Al,
That must be it then. Thanks for your input. There must be a tone
that my radio didn't pick up and instead picked only the ones at the
end of the conversation. My only question is how a user would know
the frequency is in use? Could there be some kind of indication
(maybe visual?) so he won't cause interference? Thanks again.
-Bill