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Re: Indoor Antennas



Hi, Stan.

   There are many interesting experiments for you to try to help you figure
out the answer to your question. Woody and others have already offered some.
If you are planning on using the antenna for an S-band LEO sat, you'll
probably have to add antenna gain (by using a dish, for example) to make
up for the losses from the roof components (and bird droppings ;-). The bad
part of this solution is that, as the gain of the antenna goes up, the
beamwidth of the antenna pattern gets narrower. The pointing needs to be
pretty accurate and a az/el rotor is definitely in the cards.
   P3D is different in a number of ways. First, the EIRP (emitted signal power)
in the S-band is tremendous compared to any other OSCAR to date. It will also
be farther away than a LEO. It will have an elliptical orbit which means it
will
'hang' in one place in the sky for a long period of time, making tracking
much easier. In fact, P3D's orbit has been designed so that, for any point
on Earth, the 3 'hang points' in the sky will be the same and will repeat
every 48 hours. This means you could put three antennas (small s-band
helix antennas should be MORE than enough) pointed at the three 'hang points'
in the sky and switch between them every 16 hours!!

   Bottom line-- think about an S-band helix for P3D (see James Miller's
articles on the AMSAT web site) and be ready to experiment!

Best 73's
--Paul Beckmann, wa0rse@amsat.org
   Editor, P3G for P3D


At 10:10 PM -0600 11/23/99, Stan Schretter wrote:
 >Is it possible to put an S-Band antenna in an attic, or will attenuation
 >through the roof be  too great at 2400MHz? Roof is standard asphalt
 >shingles?
 >
 >Thanks..
 >Stan W4MQ
 >
 >
 >----
 >Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
 >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org


Paul J. Beckmann, Ph.D.         e-mail: beckmann@acm.org
Beckmann Research, LLC           voice: 612-414-0302
1882 South Lane                    fax: 651-452-4103
Mendota Heights, MN 55118-4328     alt: 651-452-7145

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