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RE: Primestar dishes



 
> Since the Primestar system used a domestic Ku band satellite in the FSS 
> service, the dish as it stands has a feed built for linear polarization and 
> a minimum bandwidth of 11.7 Ghz to 12.2 Ghz.  My guess is that it will 
> probably work pretty good down to high end of 10 Ghz. Unfortunately, the 
> LNB and feed are probably integrated to form an LNBF, meaning that you just 
> cant remove the LNB. It may be possible to modify the LNBF for amature 
> frequencies.

There may be more than one version of the Primestar systems, but the one I picked up in 
the dump seems to have an LNB that will come off the feedhorn part, however it is not a 
standard lnb with rectangular flange, but instead a cylindrical one.  I haven't taken it 
apart yet, but I did try it out on regular KU sats to make sure it worked.  Of course, 
the output  of the lnbf for the 11700-12200 is down at 950-1450, ie LO=10750, so it isn't 
clear to me that perhaps it might work better at the low end of the band since the 
difference frequencies are closer to that at which the IF amps are optimized at.  Ie 
because of the LO freq I wouldn't expect it to work at all up near that freq, but it 
might work when you got further away from the LO.

> There is no reason the Primestar antennas will not work on S band, provided 
> an appropriate feed can be worked out. Two things are going to make that a 
> little difficult. The first is that the antenna is elliptical, so the feed 
> needs to have an asymetric illumination pattern.

Again, I think there must be two types of Primestar dishes out there.  While the one I 
have indeed has an offset feed, the dish itself seems to be circular, ie a regular 
parabolic shape. Ie it could be used with the Primestar feed, which has an eliptical 
opening, or with a circular feed at the prime focus.  I have seen other Primestar dishes 
that have non-circular dishes, which also probably have a different LNBF.
   In any event, these things are showing up in the trash all over the country, and at a 
minimum they can be used to pick up conventional KU TVRO  since you can pick up TVRO 
receivers very cheaply now too. Seems a shame for them to go to waste.




 
************************************
*    Bill Jones   Sweden Maine     *
* wejones@megalink.net             *
* http://www.megalink.net/~wejones *
************************************
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