[MLB-WIRELESS] xdB offset cast parabolic dishs by the hundred?

[Clae]

Another method I have seen for producing a negative parabolic mould:

Cut a parabolic curve into a piece of plywood.
Fix a bolt or some other kind of pivot, on the side opposite the 
curve, in line with the exact centre of the curve
Mount it by the pivot
Get a sandpit full of sand.
Rotate the form through the sand.
Lay fiberglass or whatever.

Obviously the sand would provide an uneven surface to the mould, 
which could then be sanded down.

Thas was for producing reflective dishes for solar thermal projects, 
so I have absolutely no idea if they would turn out accurate enough 
for radio stuff.

Clae.

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