Doug wrote
I took a tour of a CG Air Station the weekend and the helicopters have
some
kind of HF scanning system to automatically select the frequency to use to
talk to a CAMS. I wish the pilot had been knowledgeable about how it
works,
but they got the system from the US Customs Service.

That system is called COTHEN (Customs Over The Horizon Enforcement Network),
a cellular-concept of HF communications. It uses multiple transmit and
receive locations with ALE (Automatic Link Establishment) among other
technologies. This will completely replace the old guarded frequencies for
all air to ground communications. All CG aircraft are now ALE equipped, or
soon will be.

Jack Painter
Virginia Beach, Va