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Antenna Launcher
Richard Clark wrote in
: On Fri, 04 Dec 2009 20:40:09 -0500, John Ferrell wrote: What I am getting to is that you will need a plan for what to do when you pitch the weight in the tree and it don't come down! Hi John, Barring snags, time and gravity always wins. 73's Richard Clark, KB7QHC No, no, the snags are going to win. :) Friction can be a vicious mistress. Which might mean that very cold wet conditions favour the business, as it happens... One thought... how acccurate is this launcher? Any chance it can be aimed to hit the branch above target and bounce to assist further directed travel? (Sadly I wouldn't trust my stick and elastic trick with that move). |
Antenna Launcher
John Ferrell wrote:
On Fri, 04 Dec 2009 11:30:53 -0800, Bill Baka wrote: I think I have a good one for this thread. Get about 500 feet of 24 to 28 AWG magnet wire and wind it onto a fishing pole that has the easy cast and not an ocean reel. Put on a fair sized weight and then cast over the first tree in sight. Have someone walk around and find the weight on the ground and throw it over the next tree. Do this until the wire is used up or there are no more usable trees. I am going to try it on my next outing. Bill Baka SWL only. After today's experience I think I can see a problem coming for you. I was ready to move to the second tree today. After a couple of false starts (valve leaking around pipe threads & add the second battery per advice) I popped the line over the intended tree plus two more. The line ran out smoothly but stopped with a jerk. I ran out of line on the reel! The projectile was hanging about 30 feet from the ground. After much fussing around I managed to reel in enough line get to the top of the intended tree. It seems to be best to reel the line in very slowly because the projectile tends to flip around the limbs and wrap itself tightly. That is what happened to today's effort. The projectile is tightly jammed at about 65 feet up the tree with a good portion of the available line out of reach. I took the XYL to dinner and stopped by WalMart for more line for tomorrow... What I am getting to is that you will need a plan for what to do when you pitch the weight in the tree and it don't come down! 100% chance of precipitation tomorrow afternoon (may be even snow) in the North Carolina Piedmont. Great antenna weather! John Ferrell W8CCW I have a big reel of magnet wire about 22 or 24 AWG, meaning probably miles of it, so I can lose some. A lead weight is disposable so I won't cry over it. I may leave some of these antennas at favorite spots for future use. A fishing rod just casts really far for me so it is my weapon of choice. Bill Baka |
Antenna Launcher
On Fri, 4 Dec 2009 23:23:39 -0500, "Ralph Mowery"
You probably should have just cut the line off the reel and let the weight drop. When I miss, I cut the weight off and reel it back in, then reattach the weight. As mentioned, the weight will tend to wrap around places where it is not wanted. Looks like a radio day for me to John as I am just down the road near Salisbury. DE KU4PT Good advice! John Ferrell W8CCW |
Antenna Launcher
On Fri, 04 Dec 2009 22:48:38 -0600, Lostgallifreyan
wrote: No, no, the snags are going to win. :) Friction can be a vicious mistress. Which might mean that very cold wet conditions favour the business, as it happens... One thought... how acccurate is this launcher? Any chance it can be aimed to hit the branch above target and bounce to assist further directed travel? (Sadly I wouldn't trust my stick and elastic trick with that move). Too many non-precse variables for accuracy. Air pressure, temperature, elastic accumulator, projectile geometry and line drag. John Ferrell W8CCW John Ferrell W8CCW |
Antenna Launcher
On Nov 27, 12:27*pm, John Ferrell wrote:
There is an artical by W4SSY in the March 2009 QST Magazine. I am planning to duplicate it for use at my QTH. I am interested in any comments, especially from anyone who may have already built one. My available trees may be about 80 feet so that is my minimum expectations! There is a lot of Google information available but I am trying to focus on this example. John Ferrell W8CCW I wonder if my spud gun could be used for this. No compressor required. Jimmie |
Antenna Launcher
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Antenna Launcher
On 6 dic, 15:22, John Ferrell wrote:
On Fri, 04 Dec 2009 22:48:38 -0600, Lostgallifreyan wrote: No, no, the snags are going to win. :) Friction can be a vicious mistress. Which might mean that very cold wet conditions favour the business, as it happens... One thought... how acccurate is this launcher? Any chance it can be aimed to hit the branch above target and bounce to assist further directed travel? (Sadly I wouldn't trust my stick and elastic trick with that move). Too many non-precse variables for accuracy. Air pressure, temperature, elastic accumulator, projectile geometry and line drag. John Ferrell W8CCW John Ferrell W8CCW Hello John, In my opinion pneumatic systems can have good shot to shot performance. When you use projectiles of about 0.1 kg width about 25mm diameter, the required muzzle velocity is in the 25 m/s range (to reach 70 ft). As this is far below speed of sound, mass of the gas, hence temperature effect should be negligible. The weight to diameter ratio assures that air friction has less then 10% influence on height and distance. Maybe you can add something to avoid tumbling of the projectile. When you have a large bore fast opening valve ( 10ms) you should have good performance with relative low pressure (50 psi). When you experience bad repeatability, it must be the valve. If you like to experiment further, you may construct your own piston valve that interfaces directly with the barrel (coaxial structure). Over here (Netherlands), law is very strict. Even pneumatic spud guns are weapons and you may not make them as far as I know. Good luck with the launcher! Wim PA3DJS www.tetech.nl remove abc in case of PM. |
Antenna Launcher
On Dec 4, 11:48*pm, Lostgallifreyan wrote:
Richard Clark wrote : On Fri, 04 Dec 2009 20:40:09 -0500, John Ferrell wrote: What I am getting to is that you will need a plan for what to do when you pitch the weight in the tree and it don't come down! Hi John, Barring snags, time and gravity always wins. * 73's Richard Clark, KB7QHC No, no, the snags are going to win. :) Friction can be a vicious mistress.. Which might mean that very cold wet conditions favour the business, as it happens... One thought... how acccurate is this launcher? Any chance it can be aimed to hit the branch above target and bounce to assist further directed travel? (Sadly I wouldn't trust my stick and elastic trick with that move). Having tried this several different ways, my advice: Just shoot over the tree. Trying to shoot between a set of branches in the tree may sometimes make sense but I've never encountered a situation where it was best. Now, the gotcha is, if you shoot over the tree, you might also clear the 3 or 5 trees behind that! What I do is use a fishing reel and reach out and gently grab the fishing line after the ball clears the first tree. This kills the forward momentum of the ball. Then: LET GO and let the ball and line drop. Cutting a slit in the tennis ball and loading it up with washers or pennies can give it a little extra weight. Yes, I've stranded a few tennis balls in trees over the years. Tim N3QE. |
Antenna Launcher
On Dec 6, 9:42*am, JIMMIE wrote:
On Nov 27, 12:27*pm, John Ferrell wrote: There is an artical by W4SSY in the March 2009 QST Magazine. I am planning to duplicate it for use at my QTH. I am interested in any comments, especially from anyone who may have already built one. My available trees may be about 80 feet so that is my minimum expectations! There is a lot of Google information available but I am trying to focus on this example. John Ferrell W8CCW I wonder if my spud gun could be used for this. No compressor required. Jimmie Yes. My one afternoon with a spud gun was conclusive. That sucker will throw a potato hundreds of feet. My host that day insisted that nobody raise the barrel above about 30 degrees because the spuds would go over the woods and onto his neighbor's property, which we could not even see! Propellant is a one-second spritz of hair spray. Not sure what kind of line to insert through the potato, though. Kite-cord? Monofilament? |
Antenna Launcher
On Dec 11, 11:28*pm, "Sal M. Onella" wrote:
On Dec 6, 9:42*am, JIMMIE wrote: On Nov 27, 12:27*pm, John Ferrell wrote: There is an artical by W4SSY in the March 2009 QST Magazine. I am planning to duplicate it for use at my QTH. I am interested in any comments, especially from anyone who may have already built one. My available trees may be about 80 feet so that is my minimum expectations! There is a lot of Google information available but I am trying to focus on this example. John Ferrell W8CCW I wonder if my spud gun could be used for this. No compressor required. Jimmie Yes. *My one afternoon with a spud gun was conclusive. *That sucker will throw a potato hundreds of feet. *My host that day insisted that nobody raise the barrel above about 30 degrees because the spuds would go over the woods and onto his neighbor's property, which we could not even see! *Propellant is a one-second spritz of hair spray. *Not sure what kind of line to insert through the potato, though. *Kite-cord? Monofilament?- Hide quoted text - - Show quoted text - Just clamp the old Zebco on the side. Jimmie |
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