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>I bought the C4-C to upgrade my C3-E to the 40m version. Assembly pretty >straightforward so far but now I'm to the tuning jumper part and I'm a >little confused. The dimensions given for mid point, cw , etc, are they from >the center of the boom to the center of the jumper or are they measured down >the loading wire? It's says install the bend toward the outside but if I do >that I have to bend the jumper a fair amount to get it to line up? I thought >there used to be pixs on the website but I cant find them on the new >site...anyone know of any pixs somewhere that illustrate the tuning jumper? > Yes. Go to http://www.qth.com/force12/temp/techtips.htm. It is not up right now -- qth.com appears to be down -- but I found them there last week. I'm not sure how the measurements are calculated but I did it from the fiberglass spreader to the mid-point of the insulator in the element. Since the driven element in the C-4 configuration is fairly close to the mast, it is feasible to take an antenna analyser up there and adjust the spacing after you set it up on the ground. The jumpers are not very dimensionally precise, so don't worry if you have to bend them a little. One STRONG caution -- the alumo-weld wire they use for the loading wires is very strong but very brittle and prone to breakage from flexing. I mean it -- if you bend it, and then try to straighten the bend, it will probably snap the first time. The best thing to do is make the bend at the spreader a fairly large radius -- not a sharp fold -- and then make further tension adjustments on the loading wire at the stud attached to the element. There, too, heed the caution not to try to tighten it too tight, or you will have two pieces of wire in your hands. Don't pull so much tension that the element appears straight -- it needs to sag a little. I would also suggest using aluminum split bolts from Home Depot in lieu of the cable clamps that are provided with the antenna. Again, don't over-tighten, but they do provide more surface clamping area and a firmer hold than the cable clamps. 73, Pete N4ZR The World HF Contest Station Database was updated 9 May 03. Are you current? www.pvrc.org/wcsd/wcsdsearch.htm -------------------------------------------- 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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