Jon
I have a 520' loop up only 40-60 feet, we don't have many 100footers here in
western Ky at least not close to me, but here is what I did
I tried the slingshot and the old arm methods but I built the air cannon
that was in Mar 09 QST, along with many others here locally. Great distance
and pretty dang on target. But for the supports I pulled heavy fishing (trot
line) up over the tops of the trees and tied a stainless loop on it and ran
my antenna wire trough the loops and pulled the fishing line up as high as I
could. As the trees sway the wire slides in the loops.
No problems over the last 3 years.... But sure wish I had some 100 footers
:)
Good luck
John
KO4XJ
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of W4ZW
Sent: Tuesday, September 21, 2010 12:02 PM
To: 'Tower and HF antenna construction topics.'
Subject: [TowerTalk] How to support a large loop?
I?m experimenting with wire antennas here at my Breckenridge, Colorado, QTH
at 10,000?. I have the Arapahoe National Forest as my backyard with
Lodgepole pines that range up to 80-100?. I have had up in the past month a
half-square for 20M at 60? that worked great, a Windom at 70?, also worked
quite well, and full wave 80M Delta loop at 70? that really worked well.
I?ve used my bow &arrow, spinning reel, and parachute cord to get the
supports up, and have until this past week just tied the antennas up with
enough sag to compensate for the wind. When I put up the Delta Loop I used
small sailing pulleys mainly for ease in adjusting the loop after the two
support points were fixed. I also thought that letting the #14 insulated
antenna wire ?roll? through the pulleys would help with the wind.
I just received my 1000? spool of flex-weave and a spool of 450 ohm ladder
line for my next project. It will be a loop approximately 500-550? with the
lower side about 120? long at 70?, and two spans running up at about a 60
degree angle to three support points up a ridge to Lodgepole pines that will
be about 100? higher than the low end. There will be five support points in
addition to the feedline point which will be fixed.
My question is should I firmly attach the flex-weave to each insulator point
and leave enough slack for the wind, or should I use the sailing pulleys and
let the wire run through them as the wind blows?
I know that soon, there will be enough snow to perhaps seize up the pulleys
even though I coat them liberally with grease. Also does anyone have any
experience with radial ice on #14 insulated long spans?
I usually have 1 meter of snow back here, and maintenance then will be an
ordeal.
73's from 10,000'
Jon Hamlet, W4ZW/Ø
Breckenridge, Colorado 80424
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