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Re: Re: making a dish.



>While reading these messages about alternative methods
>of building a dish, I remembered a neat idea I saw once
>but which hasn't (I think) been discussed here.  While working
>on the TDRSS antennas, we needed to put together several
>dishes quickly.  One of the engineers had the idea to have
>the machine shop 'route' out the proper shape in a block of
>styrofoam and then cover the surface with aluminum tape.
>The feed was built with waveguide, which we stuck through
>a hole drilled in the center of the dish.

Does having a dielectric in close contact with the reflector make 
much of a difference in terms of reflectivity?  I know painting the 
front surface of a dish with some types of paint will drastically 
affect the dish performance, and as thin as the aluminum foil layer 
is, I was wondering if a styrofoam or other dielectric support would 
have the same effect.

Just remembering my early experience with building a wire dipole and 
discovering insulated wire elements have to be cut shorter than bare 
ones .. ;-)
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