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but > could being close to the water mitigate this somewhat? I hate to be the bearer of bad news, but salt water does NOTHING to enhance a horizontally polarized signal (well, almost nothing, maybe about 0.1 dB advantage per the models). The only advantage of being close to salt water in this case would be no noise sources in that direction, and a pretty view. Salt water ONLY enhances Vertically polarized signals. Without doing any modeling, I would also suspect that 800' from the salt water is too far. You are most concerned about the first (negative) reflection point of low take off angles being over salt water, and I suspect that 800' (at 110' effective elevation) is also too far for 40m. (In fact, N6BV, NT1N, and I were talking about his not longer than an HOUR ago! We just got back to my place after doing Visalia.) And even IF this distance was OK, you only would get enhancement of a vertically polarized signal when the path (reflection points) are over water. If you are on the center of a small island with water all around, you are in luck. But IF there is land behind the vertical, a vertically polarized signal will be significantly weaker than a horizontally one in that direction. For a vertical to be effective, salt water must be in the direction of the arriving signal. I have no doubt that the ZL9 crew got out OK, but as N6BT has been saying recently, "Everything Works". It all depends on how well... Another thing that is not obvious: if you elevate a vertical over ground (or in the case of a negative sloping hill) lobes start forming at the same rate as horizontal antennas do when you elevate them!! (basically one lobe per wavelength of elevation) But at 110', you are about ~3/4 wave high on 40m, which probably still gives you one fat lobe. > 50' is the height limit in accordance with town regulations. Alternative > of course is not to bother with 40m and go with a C3. 50' + a 60' hill and a horizontally polarized 40m signal will do VERY well. Put up the 40m elements and laugh as you beat most everyone in the pileups. I doubt you could put up a vertical array that will beat it when you are over land. Kenny K2KW Team Vertical Team Leader (6Y2A, 6Y4A, 4M7X etc.) -------------------------------------------- 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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