Snowbat wrote:
On Mon, 16 May 2005 02:01:18 +0000, Doug Smith W9WI wrote:
If you were to transmit such a signal from space, it would bounce in
pretty much the same way -- except that instead of bouncing down to a
listener on Earth, it would bounce back out into space. Not
particularly useful.

Nonsense (at least above the MUF). Consider QSOs made using Mode K (21
MHz uplink, 29 MHz downlink) of the RS-10/11 and RS-12/13 ham satellites.

I don't think that's what the OP was asking though.

Heck, we already make massive use of frequencies above the MUF for this
kind of service. Frequencies *way* above the MUF, as in above 1GHz.

Really, it would make little sense to use shortwave frequencies above
the MUF for routine service from space. The MUF changes -- a frequency
that won't bounce back into space today might bounce tomorrow. It makes
far more sense to select a frequency that's above the highest recorded E
and F-layer MUFs (i.e. at least 250MHz) and not have to worry about it.

(I wonder - but don't have the science to back it up - whether the MUF
might be considerably higher for transmissions originating in space?
Because they're striking the ionosphere at a shallower angle?)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com