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Well, I just got rg 8 cable about 20 feet for free! The thing about it
it has two pl259 connectors on it. I need to have one end free so i can wire up the slim jim or j pole I build this weekend. I really do not eant to cut the cable as I would like to use it when I put the permanent station up. See any way around this? Can I use copper house wire 12/ 2 or so to connect to the points on the j pole then bring them to a so connector Then screw the rg8 pl connector into that? Sure. One fairly common J-pole design uses an SO-239 socket which is mounted directly on one of the copper pipes at the feedpoint (use a brass screw or bolt, and then some plumber's solder). This creates the ground connection. Then, just run a short piece of copper wire from the center pin of the SO-239, across the space between the pipes, and solder it to the other pipe - this creates the "hot" side of the feed. The feedline with its PL-259 plug is screwed into the socket, and ends up sticking out to the side. See http://www.tcars.org/elmer/jpole.html for one such design, complete with a parts and materials list, and look at http://www.alpharubicon.com/elect/jpolejaden.htm for another. One design screws the SO-239 directly to the pipe, the other makes a mounting bracket. Do whichever you prefer - when properly adjusted and tuned the two designs should have performance so close to identical that you cannot tell the difference. Will this through off the swr? What ohms is 12/2 wire? No matter what attachment method you use with a standard copper-pipe J-pole, you must "match" it by adjusting the positions at which the hot and grounded side of the coax are connected to the copper pipes. As a rule of thumb, moving the attachment points upwards along the pipe causes the feedline to "see" a higher impedance. You adjust the position until your connection is at a point where the impedance is 50 ohms, and you end up with an SWR of 1:1 or close to it. The easiest way to get good results is to use a set of published plans in which the original designer has found the correct matching point, and then reproduce the antenna as exactly as you can. He also gave me a short cable with two pl 259 connectors to connect between my radio and the swr meter. It was a guy at a motorola dealer. This cable is pretty thin and not rg8 but he said it was 50 ohms. I plan on hooking the 20 feet from the swr to the antenna. Probably RG-58, and it should be fine for a short run to the SWR/power meter. -- 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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