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could do is ohm out the coax from the shield to the center conductor. It should be a fairly low value. If it is not open then you are going to have to check the coax up the tower with something like an MFJ antenna analyzer. I once took a lightning hit that significantly raised the swr. Ohmed out the feedline - I was using 1/2" hardline from the shack to the loop at the top of the tower. I determined I had an open shield. Drove me crazy. By accident I noticed a slight bulge in the hardline part way up the tower. I poked the bulge with a knife. It went right through the shield. The lightning had pulverized the shield at that point without burning the center conductor or the black plastic covering. Had to repair a 2" piece of hardline. Thank goodness the problem wasn't in the 150' buried section. Tony N2TK -----Original Message----- From: Jim Dunbar [mailto:jdunbar28@mchsi.com] Sent: Saturday, May 11, 2002 12:36 To: Force12Talk@qth.com Subject: [Force 12 Talk] Force12 C31XR SWR Problem Hello, I have been using a Force 12 C31XR with very good results at 100 feet. Recently, I noticed that my SWR climbed up to 5 : 1 on all three bands. I have semi rigid feedline going up the tower, and then I have a 15 foot run of flexible RG-8 coax between the semi-rigid feedline and the Force 12 balun that is mounted to the boom. Initially, I noticed that the two parallel feed wires between the balun and the coil were touching each other. So I climbed up the tower and separated them to the original spacing which was about 1/2 to 1 inch. However, I am still experiencing the high SWR on all three bands. The only two areas that I suspect are either the 15 foot run of RG-8 coax between the semi-rigid coax and the balun, or possibly the balun itself. Is it possible that do to a nearby lightning storm or just plain failure, that my balun may have gone bad?? I do not see any visible damage, however, the balun is sealed. Any suggestions? Thanks, Jim K4PV -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |
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