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Total 10 documents matching your query.

1. Topband: Changes To My Shunt Fed Tower (score: 1): Author: "Bob Garrett" <rgarrett5@comcast.net>; Date: Sun, 11 Dec 2011 12:21:56 -0500; Hello Topbanders, It is getting cold in the Northeast and as I get older, I dislike the cold even more. In April of this year, I replaced my Cush craft D40 40 meter rotable dipole with an OptiBeam OB; /archives//html/Topband/2011-12/msg00224.html (8,270 bytes)
2. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: "Gene Smar" <ersmar@verizon.net>; Date: Sun, 11 Dec 2011 12:30:27 -0500; Bob: Before making physical changes to the shunt feed system, can you try changing the length of the StepIR element to see if that affects the match? If it does or doesn't make a difference, that wou; /archives//html/Topband/2011-12/msg00226.html (9,297 bytes)
3. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: Herb Schoenbohm <herbs@vitelcom.net>; Date: Sun, 11 Dec 2011 14:58:51 -0400; Bob, To avoid the trips up and down the tower in the winter merely add an Omega cap from the shunt to ground, You can start with a bread slicer and replace with a fixed mica later when yu find what y; /archives//html/Topband/2011-12/msg00228.html (9,415 bytes)
4. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: Howard K2HK <k2hk@arrl.net>; Date: Sun, 11 Dec 2011 20:10:48 +0000; Sounds like both of your ideas are good ones to try first. One other suggestion is to change from a gamma to an omega match. You're pretty close now so if the snow and cold doesn't impede your trips; /archives//html/Topband/2011-12/msg00230.html (8,917 bytes)
5. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: "Mike & Coreen Smith" <ve9aa@nbnet.nb.ca>; Date: Mon, 12 Dec 2011 11:29:45 -0400; Hi Bob, If I recall (correctly).<and you should double check> The D40 is completely isolated from the mast, so it would be nearly invisible to your 160m RF...given all the other loading you have goin; /archives//html/Topband/2011-12/msg00242.html (10,587 bytes)
6. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: "Joe Subich, W4TV" <lists@subich.com>; Date: Mon, 12 Dec 2011 10:47:03 -0500; Any coax fed antenna is never isolated from the tower/mast unless the antenna switch/antenna relay is a double pole design and contained in an insulated (non-conductive) case. Even then, there is ge; /archives//html/Topband/2011-12/msg00243.html (11,934 bytes)
7. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: "DL2OBO" <dl2obo@dl2obo.de>; Date: Mon, 12 Dec 2011 17:38:20 +0100; AFAIK all Optibeam elements are always isolated from the boom. So there shouldn't be any additional toploading from them (elements), just the loading from the boom should be considered 73 Tom DL2OBO; /archives//html/Topband/2011-12/msg00246.html (11,619 bytes)
8. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: Herb Schoenbohm <herbs@vitelcom.net>; Date: Mon, 12 Dec 2011 12:48:04 -0400; Yuri, I would have to put this antenna on a different tower as I depend on my beam to give me toploading for 160...unless, they have away of connecting the elements at the center to the boom via smal; /archives//html/Topband/2011-12/msg00248.html (8,566 bytes)
9. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: W2XJ <w2xj@nyc.rr.com>; Date: Mon, 12 Dec 2011 12:05:50 -0500; The best way to handle the problem is to assume the new antenna made an impact on the match. The first step would be to measure the actual resistance and if it is not 50 ohms, reset the tap for 50 oh; /archives//html/Topband/2011-12/msg00251.html (13,491 bytes)
10. Re: Topband: Changes To My Shunt Fed Tower (score: 1): Author: Guy Olinger K2AV <olinger@bellsouth.net>; Date: Mon, 12 Dec 2011 16:15:10 -0500; Even if the beam is "insulated" from the mast or boom, any device insulating the support members of the antenna should be bypassed at these points: 1) Mast to Boom. 2) boom to longest elements farthe; /archives//html/Topband/2011-12/msg00286.html (13,419 bytes)

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