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 guide.
73,
John KD6OZH
----- Original Message ----- From: w7lrd@comcast.net To: amsat-bb@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@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