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Re: Primestar Dishes: Cheap and Frustrating

Bill - W1PA said (in part):
> I assume I would see the same if I put a 2.5 turn helix on it (Jim,
> K6CCC... didn't you write once that you thought your Primestar
> performed better with 2.5 turns?)....  the 2.5 turn helix feed now
> sized for the long dimension beam width vs. the short.

Yes I did.  I range tested my PrimeStar starting with a 7 turn (IIRC) helix
and cut it down 1/4 turn at a time all the way to only 1/4 turn.  I
measured receive signal strength at the 123 MHz IF output of my TranSystems
downconverter.  2 3/4 turned out to be maximum signal.  As part of your
discussion that I did not include here points out, that a helix this short
is likely over illuminating the dish so I am likely picking up some extra
noise due to the spillover on the truncated portions of the dish.  As my
tests only considered signal strength, that factor was not considered.

Jim Walls - K6CCC
Mobile Radio Operations
Southern California Edison Co.
Ofc:   626-302-8515   -   PAX   28-515
FAX:   626-302-7501   -   PAX   27-501

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