Re: [amsat-bb] Using C band polar mounts w/ ao-40

[Tony Dinkel <tonydinkel@xxxxxxxxxxx>]

A typical home tvro dish is pretty sloppy at its design center 
frequency of 4 gHz and would be even more so at the lower frequency 
of 2.3 gHz.  As I recall, a good 10' solid parabolic has a 3dB 
beamwidth of 3 or so degrees at 2 gHz.  Add in a little surface 
roughness or some non symmetry as is so common with a home dish and 
you end up with quite a fudge factor.  Bottom line here is...it just 
may work pretty darn good!

td


At 8:07 AM -0800 4/22/01, Edward R. Cole wrote:
>John,
>
>Good suggestions as far as you went.  Remember that TV satellite dishes
>have an additional vertical offset called "declination".  So in fact the
>dish is pointing a few degrees below the equatorial plane.  This is to
>correct for latitude when observing near-earth objects in a geostationary
>orbit.  So you would need to add the offset angle to the 5 degrees to have
>pointing correct for apogee [in other words the feed position will be 5 + 7
>degrees for mid-latitude northern hemisphere locations].
>
>The dish will still not track AO-40 over the entire orbit since it is on

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