Re: [amsat-bb] AIDC 3733 3' BBQ Dish

[K5OE@xxxxxxx]

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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