What type of feed is the best for shallow dish ?

[mauloftin]

Feed for shallow dish

Hi,
can you tell me, what type of feed is the best for shallow dish ?

I have problem with spillover in the place, where the dish ceases to shade feed. I need the feed, which have about -20 dBi at the 70° in radiation patterns.

Thank

 

[DaveN]

Re: Feed for shallow dish

Hi Mauloftin,

Although you didn't say what size dish you have, whether it is centre fed or
offset fed ( I'm assuming a centre fed) or at what frequency you intend to use it for
and that is the determining factor for its gain for a given diameter.

here is one of the best sources of easy to understand articles on dish antennae

http://www.w1ghz.org/antbook/chap4.pdf

Paul Wade, N1BWT lays it out in a way that most should understand.
He describes design, illumination, feed types, feed patterns etc
Hopefully you should find the info you are looking for

cheers
Dave N
VK2TDN
Sydney
Australia

 

[mauloftin]

Re: Feed for shallow dish

Hi,
thank for your answer. This pdf I know, is it basic pdf . I have dish f/D > 0.36, center fed. Frequency about 11 GHz. I have problem with spillover loss, exactly the spillover loss is cause high sidelobe of antenna (dish + feed). So I need feed, with very low sidelobe (about -20 dBi) and I cant find it.

I hope, that you understand me.....