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In article <VubNh.15909$tD2.5607@newsread1.news.pas.earthlink.net>,
COLIN LAMB <k7fm@teleport.com> wrote:
>"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'm 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 guarantee the accuracy of the power source. I do not guarantee my
recollection of the power level, but one battery was 'more than sufficient'
for an entire evening's operation.
The rig was home-built transistor stuff, about the size of a pack of cigarettes.
I am drawing a blank on the guy's call-sign, he lived outside Ogden Dunes, In.
>I'm 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.
Antena was a 22' solid (not mesh) parabolic dish , on a heavy-duty equatorial
mount.
He had two other, smaller, dishes, as well.
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Re: theoretical radio range....
