Bob; I don't think the larger reflector will hurt S-band feed although the larger reflector will create some additional blind spot for the dish. This may not be a problem depending on the gain required. Could you share pictures or drawings of the concentric feed? I am very interested in all options for multiband dish feeds.
Message: 3 Date: Mon, 23 Oct 2006 23:46:52 +0000 From: [email protected] Subject: [amsat-bb] L/S helix feed To: [email protected] Message-ID: 102320062346.26698.453D546C00022FD80000684A22058861720B9D04C999@comcast.net Content-Type: text/plain
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