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writes: > A few weeks ago, I posted a problem I was having with my Dxer, and or it's > coax. The problem was that when the antenna was rotated, there was an > intermitent loss of signal and the SWR would rise. This indicated a bad > coax, balun, or loose balun lead connection to the driven element. > > Replacing the LMR400 coax on both 20 and 15/17 meters with flexable Milspec > 214 solved the problem on the 20 meters but, the problem on 17/15 meters > is worse than it was before. The 15/17 meter antenna sounds dead at times > untill I apply power... then the receiver comes alive for a while as if RF > arcing somehow bridged the gap of a loose connection. The loss of signal is > still happening when the antenna is rotated or strong winds are moving the > elements about. The boom and elements are tight and the antenna is on the > tower about 2 years. > > The only thing left to check would be the balun, balun connections and > possibly the bolts and nuts that hold the balun leads to the dirven element. > I should mention that after I tightened the nuts that hold the balun leads > to the driven elements, I sprayed them with Rustoleum. I don't think this > would cause a problem since none of the paint is where it shouldn't be, all > contact points are clean an shinny. The connectors on the new cable were > installed by Cable Experts. First, have you checked the antenna at the feedpoint with an antenna analyzer? This is the first thing you do. Then work your way back through each component in order to eliminate each item. More times than not an "antenna problem" I've worked on turned out to be something in the shack - bad coax switch,bad jumper, etc. Until you can pinpoint the problem, you're just shooting in the dark. Next, if you're a member of TowerTalk - the tower and HF antenna reflector - you've heard of something called the LXC Prime Directive which is "DO what the manufacturer says". The converse of this is DON'T do what they don't tell you. Did F12 tell you to spray the antenna with spray paint? No. Methinks that's the problem and it's self-induced. Testing at the feedpoint would help to determine that. Cheers, Steve K7LXC Tower Tech -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force 12 Web site: http://www.qth.com/force12 Submissions: send to Force12Talk@qth.com To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk For problems with the list, contact n4zr@qth.com |
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