[HCARC] Compressed Air Gun - Antenna Launcher

Tue Jan 27 23:58:54 EST 2015

Well now you have gone and done it Lee.  I either may have to make the gun with threaded barrels so I can switch out the small one for a larger one to give a thrill to my Black Lab.  Never having fired one, I just figured that something small would have so much less air resistance.  HMMM, maybe get a Hand Ball or racquet ball and try that.  A smooth ball would have a tighter fit and not waste compressed air leaking through the tennis ball fuzz.  A larger caliber could also launch fishing sinker, bait leader etc down at the coast on Padre Island.  Load ball first and use it to push the sinker and rig out with the ball tethered and going only so far so you don’t lose the ball in the surf, but the sinker et al much further.   HMMMM

Gary J
N5BAA

From: Lee Besing 
Sent: Tuesday, January 27, 2015 10:40 PM
To: 'Gary J - N5BAA' ; hcarc at mailman.qth.net ; Bill Tynan ; Bryce Weathersby 
Cc: lee at besing.com 
Subject: Re: [HCARC] Compressed Air Gun - Antenna Launcher

Just remember that shooting a hard metal obje t up into the air, can be dangerous to anyone on the receiving end. 

A friend of mine, Bryce Weathersby,  KE5KFD, member of both Hill Country REACT Team and the San Antonio Radio Club, built one of these last year, using a tennis ball as the "bullet". He used his cheap Harbor Freight air compressor to pump it back up. Yes, having the gauge was very important to prevent damage. 

Knowing Bryce,  he would likely be willing to share his experience with any other interested hams as well.

Lee Besing, N5NTG
210-771-7075 ( voice/text)
San Antonio, TX

-----Original Message-----
From: Bill Tynan <billandmattie at windstream.net>
To: 'Gary J - N5BAA' <qltfnish at omniglobal.net>, hcarc at mailman.qth.net
Sent: Tue, 27 Jan 2015 10:28 PM
Subject: Re: [HCARC] Compressed Air Gun - Antenna Launcher

Gary: 

Gary: 

Very ingenious: 

Instead of the fishing sinker, you might consider the right size egg 
insulator. Since they have holes, it's easy to attach the line. 

73, 

Bill, W3XO 

-----Original Message----- 
From: HCARC [mailto:hcarc-bounces at mailman.qth.net] On Behalf Of Gary J - 
N5BAA 
Sent: Tuesday, January 27, 2015 8:50 PM 
To: hcarc at mailman.qth.net 
Subject: [HCARC] Compressed Air Gun - Antenna Launcher 

Has anyone ever made or used a PVC compressed air gun for shooting line over 
trees for putting up antennas??  I have solved all the parts including a 
rubber tire valve already installed into a PVC pipe cap and have some 1/2 
inch PVC that has a smaller inner diameter than the stuff sold at Lowes, 
which just happens to perfectly fit some 3/4 ounce steel egg shaped fishing 
sinkers available at WalMart.  The sinkers are almost a perfect fit for the 
1/2 inch PVC.  I am using a 3/4 inch PVC in-line valve for the trigger.  The 
one model I have seen in QST costs about $65.00 for $10 bucks worth of 
parts.  I plan to pump the  15-18 inch long 3 inch diameter PVC reservoir 
with between 70-100 psi of air.  The PVC is rated for 600 lbs pressure if I 
remember correctly, so my working pressures should be safe.  I am not sure 
how long to make the barrel for maximum muzzle velocity - assuming I want 
maximum muzzle velocity, since I don't want to launch the bullet all the way 
to the next county - just over a 50 + foot tree. 

All of the PVC was purchased at Lowes except for the 1/2 inch and I have 
enough to make almost anyone interested a barrel.   I'll bring the gun to 
the next meeting (assuming it passes it's beta testing of course) for 
general critique.  I am trying this method since most of attempts to utilize 
a slingshot have met with banged up fingers and a tendency for the sinker to 
curve to one side or another in flight due to the sinker being asymetrical. 
The sinkers I am using are pretty regular in shape and hopefully will fly 
pretty straight.  Once the PVC air chamber is charged with air, all it takes 
between shots is a common hand tire pump to top off the pressure for the 
next shot. 

Gary J 
N5BAA 
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Checked by AVG - www.avg.com
Version: 2015.0.5646 / Virus Database: 4273/9010 - Release Date: 01/27/15