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Re: Primestar dishes



Anybody know of where to these dishes surplus and prices?
-----Original Message-----
From: Jim White <jim@coloradosatellite.com>
To: amsat-bb@AMSAT.Org <amsat-bb@AMSAT.Org>
Date: Friday, December 10, 1999 3:50 PM
Subject: RE: [amsat-bb] Primestar dishes


>I have picked up 6 of these.  Dave at the Olde Antenna Lab is building me
>feeds for various MW bands.  He pulls the old electronics and tosses them,
>drills out the old feed, then adds a probe and a coupler to pull the signal
>out through an N connector.  We are still experimenting, but see no reason
>why this won't work.  For L or S you would need to do some mechanical work
>to replace the Ku feed with one for the right band, but this doesn't seem
>to tough.
>
>On the other hand these are big and heavy.  A thin aluminum 'snow coaster'
>or one of James' lamp shades might be easier to mount and turn, and work
>just about as well.
>
>On the other other hand, if all is successful with P3d and it reaches an
>orbit like that proposed you could bolt a PrimeStar dish on a post and not
>have to worry about rotors.  Or, since they are free, put feeds on two or
>three bolted on posts pointing E, W and whatever, cable to a single LNA
>through a switch, and switch in the one pointed at the bird.  I have 5
>acres.  I could have 20 of them :-)
>
>jw
>wd0e@amsat.org
>jim@coloradosatellite.com
>
>>
>> 
>>> 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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>>
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