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Re: [TowerTalk] tree strung dipoles

To: "" <>
Subject: Re: [TowerTalk] tree strung dipoles
From: "Jim Brown" <>
Date: Mon, 19 Oct 2009 10:07:24 -0700
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On Mon, 19 Oct 2009 11:16:20 -0400, jim Jarvis wrote:

>Based on experience, I've settled on #12 insulated flexweave wire as  
>my standard,

Flexweave is a TERRIBLE choice for any antenna that must withstand the 
high physical stress of swaying trees. I've put up a half dozen antennas 
built with Flexweave. ALL of them have broken within a year, some 

#12 solid copper should be considered a minumum for this sort of 
installation, and #10 copper is better. I use plain ordinary THHN (house 
wire). Equally important, every element of the dipole must be quite 
robust. The Alpha Delta center insulator, and the one that The Wireman 
sells are the ONLY ones to consider. The RadioWavz are AWFUL. I bought 
two to try -- both broke apart with only the weight of RG8X coax pulling 
on them. 

I've used a lot of the antenna rope that DXEnginering and others sell. 
It's quite robust, BUT it does NOT hold up to abrasion -- if the 
protective outer jacket wears (from movement on a pulley or over a 
branch) it WILL break. W3DQ recommends rope sold by the RF Connection. I 
haven't tried it yet. 

Bungee cords are also a TERRIBLE idea -- sunlight will rot them in a 
year or so. Weights are a much better solution. Some use old window 
weights. I didn't have any, so I made weights by filling big water jugs 
with dry sand. The jugs cost about $13, the sand about a buck, and the 
weight is about 90#. This works well for my 200 ft spans between trees 
at 100 ft with antennas fed with RG11. Lighter, shorter antennas require 
less weight. 

Be sure to use a good, big pulley. As I recall, Frank, W3LPL recently 
did a presentation to PVRC on this topic. I haven't seen it, but I'm 
sure it's worth finding. 

Yes, the pneumatic launcher is a winner. K2RD brought his to my QTH and 
cleared the top of my tallest redwood (170 ft) by a good 10 ft on his 
first shot. 


Jim Brown K9YC


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