Tdonaly wrote:


Since the days of Fresnel (1788-1827), this information has been known. To
admit that ham radio is 300 years behind the times is pretty sad.
--
73, Cecil http://www.qsl.net/w5dxp


O.K., Cecil, I want to make a Fresnel lens antenna for forty meters.
What does it look like,

Big.

About 1429 times larger than the one for 10GHz that was published in
'Ham Radio' some years ago. Fresnel optics (either concentric refractive
rings or concentric apertures) works perfectly well at RF wavelengths.

and how do I make one?

First hire a crane, and then...


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek