plywood fresnel

[slugworth]

4 page article scanned from october 1985 Radio Electronics magazine describing how to build a flat plywood fresnel C band dish antenna.
The lnb mounts behind it.

[Channel Hopper]

Ahh, fresnel lenses, like boom/stick antennas, are the sort of thing one looks at when there is really no other alternative, (and then give up, or bribe the man next door).

Search for Mawzone(s) and then look in your neighbourhood for something similar.

http://www.satellites.co.uk/satellit...at-dishes.html


Some interesting reading below, Fourier transforms, Maxwell and Huygens formulas abound.


_http://books.google.co.uk/books?id=Ik21bBBOYyIC&pg=PA5&lpg=PA5&dq=diffractio n+antennas&source=bl&ots=7e3KraTQnk&sig=X44aglc6KJ gKZdYp3Qin1WpFcmQ&hl=en&ei=NtsqSvrSFZTKjAfq7JD6Cg& sa=X&oi=book_result&ct=result&resnum=7#PPP12,M1

[slugworth]

I was thinking of a ku band version.
Good for areas where they won't let you have a dish antenna.
Tell them it's "a work of art".

[BombedOne]

Relatively small one for ku band can be easilly made at home, using blank PCB.

[Channel Hopper]

The problem with Ku band is the extreme bandwidth between 10.7 and 12.75 GHz.

No Fresnel design will perform well over such a range.

[BombedOne]

u can have 2 different ones, connected via 22khz switch

[slugworth]

The problem with Ku band is the extreme bandwidth between 10.7 and 12.75 GHz.

No Fresnel design will perform well over such a range.

That is the max range, but in reality the freqs are from 11.7 to 12.2 or so.(In north america anyway) see 123w as an example.

[Channel Hopper]

For that satellite at your location you could easily construct one from any bit of ply, or make a template out of a piece of aluminium if you own a jig-saw.

[slugworth]

A follow up that appeared in the feb 1986 issue of Radio Electronics correcting errors that appeared in the oct 1985 issue on plywood fesnel antennas.
Thanks to telefrancisco for pointing it out.

[TLF]

My nick here is "TLF", but thank you very much for making that available