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going to both - 85'. I tried several iterations of adding coax to the C3SS to see if I can get some gain on all 3 bands. Here is what I found out for my situation. - With equal length coax I did not see any stack gain on any bands. - By adding the distance the driven elements that have the balun attached of each antenna are from the center of the tower and multiply this by the velocity factor of the coax, I get 62". I added a 62" piece of coax to the C3SS. Now I see stacking gain on 10 and 20m - it varies from just noticeable to 2 s-units. On 15m, there is negative gain when stacked- about 2-4 s-units. - Tried different lengths of coax added to the 62" piece. I used 4" increments up to a total of 82". 10m and 20m still showed some gain. 15m just got worse. It seems the best gain was with a total length of 66" of coax added to the C3SS. It was difficult to tell the difference between 4" either way. Did a lot of running back and forth to the tower to change coax jumpers. - I wonder if the reason 15m shows negative gain is because on the C31 the feedpoint is shorted together and on the C3SS the feedpoint is joined to the coax with jumpers? Don't know if there is an easy way to do something different to help 15m? - I haven't tried something less than 62". Don't know if there is a length that would benefit 15m. At least I improved 10 and 20m. This will now allow me to improve my signal on 2 bands and also allow me to have the beams in two different directions. Even though I don't have gain on 15m, I can have the beams in two different directions to quickly switch directions. Tony N2TK -------------------------------------------- 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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