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Re: AIDC 3733 3' BBQ Dish



Ken,
I'll assume you got the 38"x26" dish from Bob, K5GNA, when you bought the 
3733.  If not, ignore the rest of this post.  My measurements and 
calculations for this dish predict a focus between 15.3636 and 15.6950".  The 
reason I don't give a single answer is because the dish is not symmetrical 
about the focus like a circular parabolic dish.   Presumably, and it would 
appear a reasonable assumption, the rectangular shape provides good phase 
alignment to a dipole's asymmetrical pattern in perpendicular orientation.  
Also, the one subjective factor in the calculations is efficiency:  I used 55 
percent.

The big question is where to place the focus--where is the phase center?  If 
you are using the stock dipole feed, I would recommend locating the focus at 
half the distance between the dipole and the reflector (as a guess).  
73,
Jerry, K5OE

k5guu@AMSAT.Org writes:
> I have several TSI AIDC 3733 Systems that I am trying to optimize for AO-40.
>  Does anyone know the diopole to dish spacing that is optimum?  I have tried
>  short, medium (~12 in.) and long and can see little difference.
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