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This is interesting, Dave.
They only give dimensions for the 2M. I assume that the #12 wire wound around the long pole is the gamma capacitor. I also wonder what the sun & time does to the insulation on this wire. In this version, the SO-239 is exposed to the WX as is the PL-259 screwed on to it. In the more usual "run-the-coax-up-to-the-feed-point-and-solder-or-clamp-it-on" method exposes the coax end to the Wx - allowing seepage into the coax. I am trying to figure out a good way to get the feed line completely INTERNAL when using the "tap-the-coax-up-a-ways-on-the-matching-section" feed method. This is so the feed line and the connector (if needed) is not exposed to the Wx. Sumptin' like this: Drill a hole in the long pole, facing the short pole, where the feed line will attach. However, if you try to solder the shield here and just extend the center insulation and center conductor to the short pole, water can enter the coax. Trying to put a SO239 or something smaller (and probably an elbow version), inside the long pole at this point (to take advantage of its "sealed" construction) is difficult. You could put a "thru joint" right below that point to improve access for soldering such a connector -- that may do it. Or you could use a pipe "T" with the lone opening facing the short pole and do something in there to use an already sealed "something" to go from the coax (inside the pipe) to the other side of the matching section. Any Ideas? "Dave Platt" wrote in message ... [...snipped...] These J-poles use a somewhat uncommon feed technique - the SO-259 is attached near the center of the crosspiece and grounded there, and the short side of the matching section is fed through a bent-wire transmission line and gamma match. http://www.pcarc.net/jpole.pdf shows the construction, including the crossbrace. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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