"COLIN LAMB" wrote in message
link.net...
"I know a ham who used to routinely work moon-bounce on VHF, with a rig
powered by a single 9v transistor radio battery. I think he had something
like 60 _milliwatts_ on transmit."

Although the statement does not give all of the facts, I am sure there is
an error. The moon is 250,000 miles away - which means a total distance
travelled of 500,000 miles. The signals must refect off a less than
perfect reflecting surface (moon dust).

I am an amateur operator and have heard signals off the moon. With modern
digital modes, there is an improvement in single signal performance - and
if the station on the other end has a giant antenna (such as the giant
radio telescope in Puerto Rico, used on occasion by amateurs having fun),
it is possible to work moonbounce with a 100 watt rig and a long single
yagi.

That is a far cry from 60 milliwatts. There is about 32 db difference
between 60 mw and 100 watts. That would mean the antenna, instead of 15
db gain for a long yagi would need to have 47 db gain. An antenna that
size might raise some neighbor's objections (blocking the sun). And,
operating it would not be routine, as an antenna with such high gain needs
to track the sun. Might need something about the size of a locomotive to
move it.

Colin


Colin,

I did some moon-bounce work back in the '70s. At the time I was using a
full 1,000 watts on 2 meters with a stack of eight 15 element circular
polarized yagi antennas. Of course the receivers are far better today and I
am sure that it can currently be done with far less power. However, like
you, it is hard for me to believe that it can be done with 60 milliwatts.

On the other hand, as you know, 60 milliwatts is adequate for a dedicated CW
QRP operator to communicate world wide using code on the 20 or 40 meters
frequency bands.

Wayne
.....................
H Wayne Paul
W7ADK
.......................
HP-14 "6F" N990
http://www.soaridaho.com/