On Fri, 17 Jul 2009 09:19:03 +0100, Geoffrey Mackenzie-Kennedy wrote: >orgetting about RF performance for a moment, wouldn't the weight of RG-8/ >RG-213 create a problem unless the antenna is supported at its feedpoint ?
I have four fan dipoles suspended at 100-120 ft between tall trees (redwoods), all fed with RG8 or RG11. There is no problem supporting the big coax. The keys to success are robust mechanical construction so that you can establish high lateral tension. If one of the objects you're suspending from is a tree, one end needs a weight and pulley to adjust to wind conditions. I use 6.5 gallon water jugs filled with dry sand (roughly 95 pounds), and the trees are typically 140-220 ft apart. I use 5/16-inch dual woven poly rope, #10 solid copper, and robust insulators. Do they sag? Sure -- at least 10 ft on the long dipoles. Does it matter? No. One of the side benefits of the big coax is that my 80/40 fans (at right angles) work quite well on 30M, 17M, 12M, and 6M, thanks to the lower loss with moderate degrees of mismatch. With relatively litte time on 6M, I've made nearly two dozen QSOs of more than 2,500 miles with my K3 and one of those dipoles. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
