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>Just received this from W5DV, > > >Any thoughts? > >Natan W6XR/2 >FORCE 12 East >Ithaca, NY >force12@qth.com > >I just took delivery on C-19XR and EF-240X last week. I had planned to >install the C-19XR at the top of the mast about 12-15 above the top of the >90 foot tower, with the EF-240X at the bottom of the mast maybe 2 feet above >the tower top. (A full sized rotary dipole for 30 meters will be attached >half-way between the two, parallel to the booms.) > >However, I wonder if it would be better to "invert" this arrangement, such >the tribander is the lower antenna. Weight and wind-loading for the C-19XR >are less than for the EF-240X, although the boom is 5 feet shorter. The >mast is a 26 foot length of galvanized steel tubing, 2 inch OD with a 7/32 >inch wall. > >Is there a "preferred" way to reduce mast stress, interaction between the >antennas, etc.? Is one of these antennas more susceptible to the need for >repairs, making it a more logical candidate for the lower mounting? > >Any experience or helpful thoughts out there? I think first you need to know whether your mast is adequate. The MARC software from Champion Radio is the easy way to solve that question. Assuming the mast is OK, my best guess is that you should leave it as is, with the EF-240X on the bottom. I have heard anecdotally of problems with relatively big 40-meter antennas, like the 240X, shadowing tribanders. Your choice of sdacing is good -- the further the better, I'd say. 73, Pete Smith N4ZR The World Contest Station Database is back up and running at http://www.qsl.net/n4zr -------------------------------------------- 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 force12@qth.com |
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