I've tried that with a 40M vertical dipole suspended with the top at
about 125 ft from a high branch in a redwood next to my house. It
worked, but a horizontal inverted V with the center at that height blows
it away in A/B comparisons. Two reasons -- there IS some absorption loss
for vertical antennas very close to trees, and for verticals in general
in dense evergreen forests. In general, that absorption increases as a
function of frequency. I live in such a forest, and the only verticals
that work well here are for 160M. And even those 160M verticals are
better than horizontal dipoles because even a dipole at 135 ft, which I
have done, is a low dipole on 160M. :)
Here are the Power Point slides for some tutorials I've done on this topic.
http://k9yc.com/VerticalHeight.pdf and
http://k9yc.com/VertOrHorizontal-Slides.pdf
http://k9yc.com/160MPacificon.pdf
73, Jim K9YC
-------- Forwarded Message --------
Subject: Re: [TowerTalk] Antennas in trees
Date: Sun, 2 Aug 2015 22:27:08 -0700
From: Edward McCann <edwmccann@yahoo.com>
To: jim@audiosystemsgroup.com <jim@audiosystemsgroup.com>
Ok.
Lots of news from the kinetic energy department.
Lots of folks have approaches to getting their balls over the tree limbs.
Si far only one response as to electromagnetic performance of antennas vertical
hanging from he tree limbs.
Anyone else have a story about a vertical dipole hanging from a tree limb not
that far from he tree, and working with vertical characteristics, like great do
low-take -off angle, etc?
Or vertical half, 5/8, or quarter wave wires hanging from tree limbs?
Thanks
AG6CX
Sent from my iPhone
On Aug 2, 2015, at 9:03 AM, Jim Brown <jim@audiosystemsgroup.com> wrote:
On Sat,8/1/2015 4:03 PM, ve4xt@mymts.net wrote:
I have no problem getting the line over a nice, tall branch but the arrow and
tennis ball get caught up on the way back down.
Here's a useful tool that my Chicago ham club bought and loaned to members.
https://www.youtube.com/watch?v=OIitgJ0M5dk
http://www.sherrilltree.com/Big-Shot-Standard-Kit#.Vb47__lVhBc
http://www.sherrilltree.com/Sherrill-Throwbag#.Vb47W_lVhBc
http://www.sherrilltree.com/BIG-SHOT-Line-Reel#.Vb48NPlVhBc
You will occasionally lose weights. Fishing weights can be used to launch the
line, but their visibility is poor, so they're hard to find.
Here's the other popular product, clearly the best. K2RD brought his to my QTH
soon after I moved here and cleared the top of a 175' redwood on his first shot.
You can buy replacement weights for both products. Some trees are much worse than others
for snagging them. The smaller and smoother they are, the less likely the weights are to
snag. It's often possible to "worry" the line back and forth to clear branches.
73, Jim K9YC
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