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Re: Using C band polar mounts w/ ao-40



Your thinking is quite correct.  Yes, surface inaccuracy will have 
less of an impact at a lower frequency.  My point was a 10 foot 
antenna is not a big pointing challenge at S band.  That fact and the 
cumulative errors inherent in a home tvro antenna just may be in 
favor of making it work pretty good.

I for one would like to try it with mine.  I have been looking for an 
excuse to build another coffee can feed horn.  Fortunately, I have a 
rare tvro dish with both az and el actuators so el tracking will not 
be a problem for me.  Unfortunately, my controller is long gone so I 
am going to have to build one and maybe even write some code.

Still a hardware guy,
Tony Dinkel
WB6MIE
http://www.tonydinkel.dynip.com/



At 1:29 PM -0700 4/21/08, KB7WW Art Moe wrote:
>Maybe my theory and thinking is wrong, but lets say that a dish has
>a surface error of .5 wave length at 4 Ghz then it would only have an
>error of .25 at 2 Ghz making it BETTER. Or am I thinking wrong.
>Although at 2 Ghz it still has less gain than at 4 Ghz.
>
>
>Art
>KB7WW
>
>Tony Dinkel wrote:
> >
> > 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

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