Well its not a black art, all aerials still obey the same rules, its just
the compromises made in the design. I recall these were used in millimetric
radar systems and the main reason was that they needed to be able to steer
them electronically. Not tried the scaled up versions, I have to say.
Brian

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From the Sofa of Brian Gaff Reply address is active
"Capitol" wrote in message
o.uk...

Does anyone have any experience of these? The plots I've seen seem to have
very variable gain/frequency responses.