# RE: Repeators in Space

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> -----Original Message-----
> From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
> Behalf Of Steve Howland
> Sent: Monday, December 24, 2001 9:28 AM
> To: AMSAT
> Subject: [amsat-bb] Repeators in Space
>
>
>
> wondering : how long did it take a signal to reach the moon from
> earth or vice versa during the Apollo missions ?

Assuming the moon remains at a constant 250k miles (which it does
not), it would take 1.344 seconds one way, or 2.688 seconds round
trip.  This is assuming my brain is functioning this early.

> As well, how long does it take a signal to reach our Mars probes
> and landers that we have had ?

All depends on distance.  Pretty much, radio waves run at the speed
of light.  Pick your object, find its distance, and do the math.

> Do you think it might be possible in future missions to place
> machines in space that would act as repeaters between distant
> places so that we might cut or eliminate the time that it takes for
> a signal to reach earth ?

No.  Repeaters can boost power, and provide more coverage, but
one thing they cannot do is speed up the speed of light.  In fact,
a poorly designed repeater might add a bit more delay.  Also, as
a concept it sounds good, but as more weight on a launch, it might
not be welcome.  And to pay full price for a ride is more than my
little group can come up with.

> From listening to Sputnik 41, I understand that there were amazing
> things that could be done with just 500 miliwatts while it was in our
> orbit.  Just think what we might do with such a "space buoy " like a
> 30 or 50 watt-er placed between us and some distant location.

The repeater on the moon idea has been discussed often enough.
The main problems would be:  1.  If it were an FM repeater, it would
sound just like AO-27 and UO-14.  Fun, but not real good for real
communications.  2.  It would be on the dark side of the moon for two
weeks of every orbit, or 1/2 the time.  Build 2 of them, and command
the one going into darkness off, and command the one coming out of
darkness on maybe.  Then you still have a problem with temperature.
It would freeze on the dark side, and bake in the sunlight.  All but the
solar panels could be shielded against heat, but insulating against the
bitter dark cold would be a trick I think.  Freeze the batteries and
it might be finished.

Possible a transponder, such ad AO-40, set on one of the moons poles
might be an idea, provided the other problems could be overcome.

> Every dream has to be born some place.  These are the thoughts
> that lead to invention, don't you think ?

Yep... it is interesting.  Be sure to let us know when it is ready for
launch.

>     73' and Merry Christmas
>      de ' KF4FQT

A safe and Happy Holiday Season to all.

Mike.  KD9KC.

If you are in a place where 180 men can be outnumbered, outfought,
and it is still called a victory, where it isn't real food unless it makes
you cry, and where even the state mascot is armor plated, you must
be in TEXAS.
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