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Old October 22nd 05, 06:23 AM
SR
 
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Default Moon Bounce

That's amazing. Who thought about doing that? Who invented that idea?
Did the Russians ever found out?


SR

SeeingEyeDog wrote:

Before satellites became available for eavesdropping the moon was used to
listen to the USSR.

"SR" wrote in message
...

The last few evening the moon was almost full and the evening sky was
fairly clear here in New York. I then transmitted on my CB but no DX
only locals.

I read something somewhere that mention about Moon Bouncing. Meaning
that a signal can travel far. But I am not sure if that is true.

73 SR!




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Old October 22nd 05, 01:33 AM
Mark Zenier
 
Posts: n/a
Default Moon Bounce

In article , SR wrote:
The last few evening the moon was almost full and the evening sky was
fairly clear here in New York. I then transmitted on my CB but no DX
only locals.

I read something somewhere that mention about Moon Bouncing. Meaning
that a signal can travel far. But I am not sure if that is true.


It's a VHF and microwave thing. You actually illuminate the Moon
with enough power that another station back on Earth can pick up
the reflection. But that requires an antenna that can focus most
of your power on the Moon, a target only 1/2 degree across. Hams,
with 1 kilowatt, can get morse code and slow digital signals (on the
higher bands).

Before satellites the Defense Department was able to send several
teletype channels at at time, maritime mobile. That was with a big dish
and probably 10's of kilowatts. (The best description of using that
equipment, that I've seen, was in a description of the incident where the
USS Liberty, the radio intelligence ship, was attacked by the Israelis.
In the Atlantic Monthly about 10-15 years ago, as I remember).

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

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Old October 23rd 05, 06:02 AM
matt weber
 
Posts: n/a
Default Moon Bounce

On Sat, 22 Oct 2005 00:33:19 GMT, (Mark Zenier)
wrote:

In article , SR wrote:
The last few evening the moon was almost full and the evening sky was
fairly clear here in New York. I then transmitted on my CB but no DX
only locals.

I read something somewhere that mention about Moon Bouncing. Meaning
that a signal can travel far. But I am not sure if that is true.


It's a VHF and microwave thing. You actually illuminate the Moon
with enough power that another station back on Earth can pick up
the reflection. But that requires an antenna that can focus most
of your power on the Moon, a target only 1/2 degree across. Hams,
with 1 kilowatt, can get morse code and slow digital signals (on the
higher bands).

I believe it was first done in the 6 meter band in the 1950's/

Before satellites the Defense Department was able to send several
teletype channels at at time, maritime mobile. That was with a big dish
and probably 10's of kilowatts. (The best description of using that
equipment, that I've seen, was in a description of the incident where the
USS Liberty, the radio intelligence ship, was attacked by the Israelis.
In the Atlantic Monthly about 10-15 years ago, as I remember).


Yes, but that wasn't moonbounce, it was tropo scatter. YOu can only
use Moonbounce when the moon is visible to both ends. Troposcatter
works just about anytime, anywhere. The change in permittivity at the
top of the toposphere will actually bounce a tiny portion of the
microwave signal back down quite reliably. You can get about 600
miles that way. But you need the sort of big dish, and tens of
kilowatts to do it reliably. Only the military could really afford to
use it.


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Old October 23rd 05, 09:23 AM
Brad
 
Posts: n/a
Default Moon Bounce


"Frank Dresser" wrote in message
news:ZCH6f.169781$qY1.131220@bgtnsc04-
The USS Liberty is said to have had moonbounce capability. The moonbounce
antenna is supposed to have been one of the distinctions seperating it
from
the Egyptian ship the Isrealis said they thought they were attacking.

The large parabolic antenna in the picture, pointing straight up, seems to
be that moonbounce antenna.

http://www.history.navy.mil/photos/i...00/u123118.jpg

Frank Dresser


Isn't the internet a constantly amazing resource? By crikey, there is not a
thing you cannot find on it!

Brad.







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Old October 23rd 05, 09:25 AM
Brad
 
Posts: n/a
Default Moon Bounce


"Frank Dresser" wrote in message
...

The large parabolic antenna in the picture, pointing straight up, seems to
be that moonbounce antenna.

http://www.history.navy.mil/photos/i...00/u123118.jpg

Frank Dresser


You know, that could just be the position the antenna is parked. It might be
a bit of an assumption that the moon is straight up! ;-)

Brad.


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Old October 23rd 05, 03:20 PM
Frank Dresser
 
Posts: n/a
Default Moon Bounce


"Brad" bradvk2qq AT w6ir.com wrote in message
...

"Frank Dresser" wrote in message
...

The large parabolic antenna in the picture, pointing straight up, seems

to
be that moonbounce antenna.

http://www.history.navy.mil/photos/i...00/u123118.jpg

Frank Dresser


You know, that could just be the position the antenna is parked. It might

be
a bit of an assumption that the moon is straight up! ;-)

Brad.



I'd assume that antenna could be pointed anywhere from horizon to horizon.

Frank Dresser


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Old October 24th 05, 09:42 AM
 
Posts: n/a
Default Moon Bounce

On Sun, 23 Oct 2005 18:25:07 +1000, "Brad" bradvk2qq AT w6ir.com
wrote:


"Frank Dresser" wrote in message
...

The large parabolic antenna in the picture, pointing straight up, seems to
be that moonbounce antenna.

http://www.history.navy.mil/photos/i...00/u123118.jpg

Frank Dresser


You know, that could just be the position the antenna is parked. It might be
a bit of an assumption that the moon is straight up! ;-)

Brad.


Reading closely, you would see that there was no implication
in the previous posting that the antenna was actively in use. Yes, it
may have been parked, under maintenance or so positioned for any
number of other reasons.



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Old October 24th 05, 04:22 AM
matt weber
 
Posts: n/a
Default Moon Bounce

On Sun, 23 Oct 2005 08:13:45 GMT, "Frank Dresser"
wrote:


"matt weber" wrote in message
.. .
On Sat, 22 Oct 2005 00:33:19 GMT, (Mark Zenier)
wrote:

[snip]

Before satellites the Defense Department was able to send several
teletype channels at at time, maritime mobile. That was with a big dish
and probably 10's of kilowatts. (The best description of using that
equipment, that I've seen, was in a description of the incident where the
USS Liberty, the radio intelligence ship, was attacked by the Israelis.
In the Atlantic Monthly about 10-15 years ago, as I remember).


Yes, but that wasn't moonbounce, it was tropo scatter. YOu can only
use Moonbounce when the moon is visible to both ends. Troposcatter
works just about anytime, anywhere. The change in permittivity at the
top of the toposphere will actually bounce a tiny portion of the
microwave signal back down quite reliably. You can get about 600
miles that way. But you need the sort of big dish, and tens of
kilowatts to do it reliably. Only the military could really afford to
use it.



The USS Liberty is said to have had moonbounce capability. The moonbounce
antenna is supposed to have been one of the distinctions seperating it from
the Egyptian ship the Isrealis said they thought they were attacking.

The large parabolic antenna in the picture, pointing straight up, seems to
be that moonbounce antenna.

http://www.history.navy.mil/photos/i...00/u123118.jpg

Frank Dresser

Having it pointed straight up is the standard stowed position. At lot
less load on the mounting that way. However it could just as easily be
a tropo scatter antenna, and tropo scatter has the advantage that the
moon doesn't have to visible at both ends of the path.

however it could also have used a communication satellite. I think
only Syncom III was in Geo Syncrhonos orbit at that time, however
there were a number of other sats in LEO and MEO (such as Telstar)
that could have been used, and they would come into view every few
hours and would be usable for 15-30 minutes at a time with a usable
bandwidht of a few MHZ. The Syncom III video wasn't so great, since it
was a 2 Mhz transponder IIRC, and analog Television is 6Mhz.

.. The first Telstar went up in 1962, and I would be indeed surprised
is several Military sats didn't have similar capabilities at that
time. In the fall of 1967 I remember a professor of Meteoroloby at the
University of Wisconsin telling me about a single UHF transponder they
had put on one of the Tiros weather sats in orbit that could be used
(and was used as a voice channel). The roof of the Meteorology
department at UW had a modest steerable corner reflector to use it..
As it was in LEO, it only took about 50 watts on each end.
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Old October 24th 05, 08:58 AM
Frank Dresser
 
Posts: n/a
Default Moon Bounce


"matt weber" wrote in message
...
On Sun, 23 Oct 2005 08:13:45 GMT, "Frank Dresser"
wrote:



Having it pointed straight up is the standard stowed position. At lot
less load on the mounting that way. However it could just as easily be
a tropo scatter antenna, and tropo scatter has the advantage that the
moon doesn't have to visible at both ends of the path.


Wouldn't a moonbounce setup, with high power and a steerable antenna, also
have tropo scatter capability? It wouldn't necessarly go the other way,
however. Equipment which works well enough for tropo scatter might not do
the moonbounce job.


however it could also have used a communication satellite. I think
only Syncom III was in Geo Syncrhonos orbit at that time, however
there were a number of other sats in LEO and MEO (such as Telstar)
that could have been used, and they would come into view every few
hours and would be usable for 15-30 minutes at a time with a usable
bandwidht of a few MHZ. The Syncom III video wasn't so great, since it
was a 2 Mhz transponder IIRC, and analog Television is 6Mhz.

. The first Telstar went up in 1962, and I would be indeed surprised
is several Military sats didn't have similar capabilities at that
time. In the fall of 1967 I remember a professor of Meteoroloby at the
University of Wisconsin telling me about a single UHF transponder they
had put on one of the Tiros weather sats in orbit that could be used
(and was used as a voice channel). The roof of the Meteorology
department at UW had a modest steerable corner reflector to use it..
As it was in LEO, it only took about 50 watts on each end.


Again, what works for moonbounce ought to more than meet the standard for
satellite work.

The Liberty was said to have had moonbounce capability. I'd figure they
used that large parabolic antenna for that purpose. There's no obvious
reason they couldn't have used it for the less demanding tasks of tropo
scatter and satellite comms.

Frank Dresser




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