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[TowerTalk] Tennis ball launcher

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Subject: [TowerTalk] Tennis ball launcher
From: "W7ZZ" <w7zz@wavecable.com>
Date: Mon, 26 Dec 2011 10:55:10 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I use an antenna shooter based on an article that appeared in QST about 18 
months ago,a design later modified by a member of the Radio Club of Tacoma.  It 
shoots a PVC projectile easily 150' in the air and yet the projectile is heavy 
enough to pull the fishing line down on the other side.  I use a yellow 60 
pound test dacron line -- easy to see in the tree and wears like iron.  It is 
very easy to aim, unless it is windy.  If you want to shoot something lower 
than the maximum height, you just fill the air tank with less pressure.  I use 
a bicycle pump that has an accurate pressure meter on it but my shooter also 
has a pressure guage.  If the two differ, I use the average of the two.  You 
shoot the projectile over the tree (or limb of your choosing -- it's pretty 
easy to aim) and then cut off the projectile, replacing it with light line (I 
use 550 parachute cord).  You then reel the parachute cord back over the tree.  
If need be, you can then pull a heavy line back using the pa
 rachute cord to pull it with.  The parachute cord is incredibly strong, wears 
like iron and has stretch built in, which adds some shock absorption to the 
system.  

The North Kitsap Amateur Radio Club sells a tennis ball launcher that shoots 
weighted tennis balls.  It's much smaller than my launcher and works even 
better.  When mine eventually breaks, which it will as the components are all 
ABS or PVC, I'll buy one, they're so good.  Again, using colored balls and 
line, it's very easy to work with even in dense foliage/trees.  They use a 12 
volt air compressor to fill the shooter, but a bike pump would work just fine.  
The NKARC shooter has a pressure guage and uses a trigger release valve system 
(mine uses a PVC shutoff valve -- more crude, but works just fine).  I suggest 
you contact W7PV, Paul Voorhees, and see if there are any "in stock" at the 
moment.  I think they go for $150 and worth every penny.  Here's Paul's email:  
ropavo@gmail.com  I will copy him on this message so that he knows this is 
being blasted out to the TowerTalk reflector.

By the way, for years I used the slingshot/closed face spinning reel method.  
In my opinion, it's dangerous and I had many fishing sinkers swaying in tree 
branches way up in the air when the sinker spun around a branch rather than 
passing through it like a tennis ball or my PVC projectile would do. Sooner or 
later, those are going to fall and hopefully there won't be anyone underneath 
at that moment.  Also, on occasion, the sinker will hit the tree trunk or a 
branch at high velocity and then it can bounce straight back at the shooter --- 
very dangerous, it happens so fast you can't even get out of the way.  Having 
said that, I confess that I still use this method if I don't want to shoot very 
high. The antenna shooters described above don't work very well at lower 
heights.

73, Doug W7ZZ
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