Posted by
Geoffrey Mackenzie-Kennedy on
Jul 22, 2009; 11:29am
URL: http://elecraft.85.s1.nabble.com/OT-Balanced-Feedlines-tp3273430p3302506.html
Good morning Jim,
Thanks for your e-mail. I also use tall trees to support antenna catenarys,
which are made from 6mm dia woven marine rope, along with marine pulleys,
and a counterweight at one end of each catenary. The counterweight for each
catenarys is "fused", so if another tall tree falls across a catenary or
antenna during a storm, the catenary/ antenna will come down under the tree
without serious damage, and the rope will still be running through the
support pulley which makes it easy to hoist again after the fallen tree is
removed.
At one time I used airborne coax feeders here but replaced them with open
wire feeders, after somebody shooting pheasant on the farm filled a coax
feeder with lead shot.
73,
Geoff
GM4ESD
On Wednesday, July 22, 2009 at 6:03 AM, Jim Brown wrote:
> 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
No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.392 / Virus Database: 270.13.23/2254 - Release Date: 07/22/09
05:59:00
______________________________________________________________
Elecraft mailing list
Home:
http://mailman.qth.net/mailman/listinfo/elecraftHelp:
http://mailman.qth.net/mmfaq.htmPost: mailto:
[hidden email]
This list hosted by:
http://www.qsl.netPlease help support this email list:
http://www.qsl.net/donate.html