Guess I learned the ITU version :-) http://en.wikipedia.org/wiki/Simplex_communication On Tuesday, June 7, 2011, Nigel Gunn G8IFF/W8IFF <nigel at ngunn.net> wrote: > That's half duplex, not simplex. > > On 07-Jun-11 14:55, Justin Pinnix wrote: > > A packet satellite can also be operated simplex (TX and RX on the same > frequency). > >