[amsat-bb] Re: L/S helix feed

John B. Stephensen kd6ozh at comcast.net
Mon Oct 23 21:11:37 PDT 2006

It should be easy to make a high-pass filter that removes the 1.2 GHz 
signal. A piece of waveguide with two coaxial to waveguide transitions will 
reject everything longer than 1/2-wavelegth in the long dimension of the 



----- Original Message ----- 
From: <w7lrd at comcast.net>
To: <amsat-bb at amsat.org>
Sent: Monday, October 23, 2006 23:46 UTC
Subject: [amsat-bb] L/S helix feed

> Hello
> Questions on my current L/S helix feed.
> I am building a dual L/S concentric helix feed for a 48x54 inch primestar 
> dish.  The reflector is cut for  L band does that cause a problem with S 
> band?  Where can I find a good design for a notch filter for S band to 
> reduce desense?  Where does the focal point want to be on the helicies? 
> Or is it pretty forgiving.  Any other information is appreciated.
> 73 Bob W7LRD
> Seattle
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb 

More information about the AMSAT-BB mailing list