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[TowerTalk] Fwd: Re: Antennas in trees

To: towertalk reflector <towertalk@contesting.com>
Subject: [TowerTalk] Fwd: Re: Antennas in trees
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Mon, 3 Aug 2015 14:24:57 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
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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