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[TowerTalk] RE: Horizontal Loops

 To: [TowerTalk] RE: Horizontal Loops "Merle Bone" Sun, 15 Aug 2004 13:24:03 -0500
 ```"If a folded dipole performs like a normal dipole, why doesn't a horizontal loop perform like a rhombic ?" ............................................ If constructed as a rectangle, a loop can exhibit lobes and gain similar to a rhombic on frequencies where the legs are "long" with respect to the frequency wavelength. I use an 80 meter horizontal loop which is a rectangle with the corners at 30 to 40 feet high. The north/south legs are longer then the east/west legs and the southern corners are higher then the northern corners. When fed at one of the corners, the loop has definite lobes, with gain, above 20 Meters- - 20-17-15-12-10 Meters. The pattern changes with frequency and tends to go from a wider corner lobe on 20 meters to narrower corner lobes on 10 Meters. Changing the corner which is fed also moves the direction of the major lobes(My pattern comparisons are done with a rotatable yagi). Naturally, the maximum take-off angle drops as the frequency is raised. I recently changed the feed-point to maximize the lobe towards Asia rather then Europe with good results, as predicted by the antenna model. Again, this is with a specific design loop. As indicated earlier, random loops will give random patters. My loop becomes a "sky-warmer" on 40 and 80 Meters with very little directionality - more like a "low dipole." I also feed the loop with a 9:1 balun at the feed-point. This brings the loop SWR down to less then 3:1 on 20 through 10 Meters. Loops can yield interesting results, depending on the shape and height of the loop. Merle Bone _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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