Hello:

Have never gotten into monitoring any Maritime HF voice communications, but
thought it might be interesting, so let
me ask, please, a few really basic questions.

Ship to shore and shore to ship voice and phone comms: are these (usually)
via simplex or duplex channels ?

If both, who uses what, etc. ?

Any good frequencies to try ? Usually USB ?

Guess I would prefer to hear both sides of a conversation, if possible, so
would prefer to
try duplex used freq's (at least initially)

How about C.G. VHF: are these simplex or duplex usually ?

Thanks,
Bob