Antenna Launcher
 

On Mon, 30 Nov 2009 10:31:12 -0800, Jim Lux
wrote:



3 9V batteries in series makes a fine source to actuate a sprinkler
valve. Put a 0.1 uf (or thereabouts, non critical) capacitor across the
pushbutton contacts to make it last a bit longer.

Got a little further today. It takes too many hands to twist the
valve, fiddle with the reel and aim the device. I black vinyl taped a
micro switch to the valve assembly with ONE 9 volt battery so that I
can thumb it to launch. I also moved the open face reel back to the
valve end of the barrel and fabricated (more black tape & paperclip)
an eye to pass the line through so that line retrieval with the reel
is less awkward. Today's final test was conducted in the dark so I was
unable to see much. I launched nearly 90 degrees and it was gone for
several seconds so I expect it did well.

VK2KC emailed me with some advice. He pointed out that it is usually
better to launch from the woods to an open space. I expect that will
be the case.

It seems to me that this device consists of three components: Barrel,
Valve and accumulator. It seems that to change to launching tennis
balls would be a matter of fitting a 2-1/2" barrel. I doubt that I am
going to find that in my area but I will keep my eyes open.

Tomorrow is another day!

John Ferrell W8CCW

Antenna Launcher
 

John Ferrell wrote in
:

On Mon, 30 Nov 2009 10:31:12 -0800, Jim Lux
wrote:



3 9V batteries in series makes a fine source to actuate a sprinkler
valve. Put a 0.1 uf (or thereabouts, non critical) capacitor across the
pushbutton contacts to make it last a bit longer.

Got a little further today. It takes too many hands to twist the
valve, fiddle with the reel and aim the device. I black vinyl taped a
micro switch to the valve assembly with ONE 9 volt battery so that I
can thumb it to launch. I also moved the open face reel back to the
valve end of the barrel and fabricated (more black tape & paperclip)
an eye to pass the line through so that line retrieval with the reel
is less awkward. Today's final test was conducted in the dark so I was
unable to see much. I launched nearly 90 degrees and it was gone for
several seconds so I expect it did well.

VK2KC emailed me with some advice. He pointed out that it is usually
better to launch from the woods to an open space. I expect that will
be the case.

It seems to me that this device consists of three components: Barrel,
Valve and accumulator. It seems that to change to launching tennis
balls would be a matter of fitting a 2-1/2" barrel. I doubt that I am
going to find that in my area but I will keep my eyes open.

Tomorrow is another day!

John Ferrell W8CCW


Sorry if my post is as silly as it appears it might be, but just in case it
isn't... I've seen people walking dogs in a large park I run in a lot. They
have these slingshot/stick type affairs to throw tennis balls with for fast
strong dogs to get a lot of exercise fetching them while the owner has an
easier time of it. I've never tried one, but from what I've seen, even
unconscious practise seems to result in some accuracy, and distance certainly
isn't lacking. In short, it might be easier, cheaper and faster to practise
with one of those than to devise a more complex launcher. It seems to me that
accurately placing a thin line over a branch up to 100 ft high might be
easier than learning to fly-cast.

Another thing I remember, on a smaller scale by far, is a small stick and two
rubber bands, one binding the other over the end of the stick. I was about 6,
at a strange house competing with another boy to accurately and strongly
catapult nasturtium seeds by releasing them against the stick so the band
drew them near-parallel to it at speed. It's very effective because it eases
aiming and the recoil is just enough to cause the stick end to slew aside to
allow accurate clearance at the crucial instant, something that became
immediately apparent at the time I 'invented' it. If the thing were scaled
up, for example with a carefully prepared inner tube from a cycle tyre, then
maybe the thing can launch a weighted tennis ball and light line accurately
with one shot. The trial and error would certainly be a lot lower than the
dog-ball-slinger. :)

Antenna Launcher
 

John Ferrell wrote:
On Mon, 30 Nov 2009 10:31:12 -0800, Jim Lux
wrote:


3 9V batteries in series makes a fine source to actuate a sprinkler
valve. Put a 0.1 uf (or thereabouts, non critical) capacitor across the
pushbutton contacts to make it last a bit longer.

Got a little further today. It takes too many hands to twist the
valve, fiddle with the reel and aim the device. I black vinyl taped a
micro switch to the valve assembly with ONE 9 volt battery so that I
can thumb it to launch. I also moved the open face reel back to the
valve end of the barrel and fabricated (more black tape & paperclip)
an eye to pass the line through so that line retrieval with the reel
is less awkward. Today's final test was conducted in the dark so I was
unable to see much. I launched nearly 90 degrees and it was gone for
several seconds so I expect it did well.

I've found that a single 9V will open a valve if there's not much
pressure, the coil is cool, etc. Run the pressure up, grab the thing
out of the back of the car where it's been cooking in the sun, etc. and
a bit more current through the coil is handy. (Oh yeah, and with 3
alkaline 9Vs, they'll last basically forever, because it will still fire
when they're almost dead... use the ones you pulled out of your smoke
alarms at home)


VK2KC emailed me with some advice. He pointed out that it is usually
better to launch from the woods to an open space. I expect that will
be the case.

It seems to me that this device consists of three components: Barrel,
Valve and accumulator. It seems that to change to launching tennis
balls would be a matter of fitting a 2-1/2" barrel. I doubt that I am
going to find that in my area but I will keep my eyes open.

Don't neglect the possibility of using a slightly large barrel with a
liner (take a bigger diameter piece of plastic pipe, use a circular saw
to rip a slot down the length, and then squeeze it down to fit inside
the outer tube.

Or a sabot/piston made of closed cell foam (e.g. cut a disc of styrofoam
that fits snugly.. or I like polyethylene foam.. it's a bit springier)

Or, use one of those squishy fairly dense foam rubber balls (you see
them as "stress relievers" as a giveaway at trade show booths, for
instance) that are available in a variety of sizes and make a snug fit
with the ID of whatever barrel you use.



Tomorrow is another day!

John Ferrell W8CCW

Antenna Launcher
 

On Wed, 02 Dec 2009 03:04:48 -0600, Lostgallifreyan
wrote:


Sorry if my post is as silly as it appears it might be, but just in case it
isn't... I've seen people walking dogs in a large park I run in a lot. They
have these slingshot/stick type affairs to throw tennis balls with for fast
strong dogs to get a lot of exercise fetching them while the owner has an
easier time of it. I've never tried one, but from what I've seen, even
unconscious practise seems to result in some accuracy, and distance certainly
isn't lacking. In short, it might be easier, cheaper and faster to practise
with one of those than to devise a more complex launcher. It seems to me that
accurately placing a thin line over a branch up to 100 ft high might be
easier than learning to fly-cast.

Another thing I remember, on a smaller scale by far, is a small stick and two
rubber bands, one binding the other over the end of the stick. I was about 6,
at a strange house competing with another boy to accurately and strongly
catapult nasturtium seeds by releasing them against the stick so the band
drew them near-parallel to it at speed. It's very effective because it eases
aiming and the recoil is just enough to cause the stick end to slew aside to
allow accurate clearance at the crucial instant, something that became
immediately apparent at the time I 'invented' it. If the thing were scaled
up, for example with a carefully prepared inner tube from a cycle tyre, then
maybe the thing can launch a weighted tennis ball and light line accurately
with one shot. The trial and error would certainly be a lot lower than the
dog-ball-slinger. :)

I am still open to all leads. I did a Google on "dog ball shooter" and
found a lot of interesting posts. I don't think any of them are up to
carrying a monofilament line over a 100 foot tree but they are still
interesting. My Black Lab enjoys chasing a genuine bowling pin when I
throw it but we are both getting too old for that game! It has given
her very strong neck muscles.

The Hyper dog launcher looks to be effective and inexpensive for the
intended purpose.

I met a fellow at Home Depot that does a lot of surf fishing in the
ocean. He is considering a similar device as my launcher to place his
bait further from the beach...

Rainy day (flood warnings) in North Carolina today... antenna play on
computer today.

John Ferrell W8CCW

Antenna Launcher
 

John Ferrell wrote in
:

I am still open to all leads. I did a Google on "dog ball shooter" and
found a lot of interesting posts. I don't think any of them are up to
carrying a monofilament line over a 100 foot tree but they are still
interesting. My Black Lab enjoys chasing a genuine bowling pin when I
throw it but we are both getting too old for that game! It has given
her very strong neck muscles.

The Hyper dog launcher looks to be effective and inexpensive for the
intended purpose.

I met a fellow at Home Depot that does a lot of surf fishing in the
ocean. He is considering a similar device as my launcher to place his
bait further from the beach...

Rainy day (flood warnings) in North Carolina today... antenna play on
computer today.

John Ferrell W8CCW


One thing I didn't catch was how often you might need to relaunch.. If lots,
then for consistency your gadget will win easily. I'd still try the inner-
tube elastic and 3 foot stick wheeze though. I also tried making bows and
arrows as a kid and was hopeless, but the straight-stick catapult really
scored.. (I'm surrounded by 4-floor buildings though so this is sort of
rhetorical, I couldn't actually do it on anything but a short trajectory to
ground here without breaking something).

Antenna Launcher
 

On Sun, 29 Nov 2009 20:11:29 -0500, "Ralph Mowery"
wrote:

You do not need the projectile to be very tight.
I just used some electrical tape to make it fit beter. Used orange as I
though it might make it easier to find .

Yech. One of the local hams was trying to use one and had the same
fit problem. Somehow, I got involved. The first thing I did was toss
a little household flour into the launch tube so I could see if the
ball was leaking. Someone appeared up with a camcorder that would do
about slow motion. Kinda like that TV show that shows things in slow
motion. The tennis ball leaked really badly.

Time to fix the leak. I decide to make a new projectile in the shape
of a Civil War Minie Ball.
http://en.wikipedia.org/wiki/Mini%C3%A9_ball
The idea was to have a conical head for improved aerodynamics and an
expanding base for a good seal. Of course, friction had to be
minimal. To improve the seal, I found some close cell urethane foam.
Using a hot nichrome wire, I cut a simple cylinder that was slightly
smaller than the bore diameter, and about the length of a beer can.
Well, it was the exact size of a beer can because that was what we
were launching nearby with a propane powered canon. Anyway, I also
used the hot wire to form a somewhat conical cavity in the base. Air
pressure would expand the base outward towards the barrel wall,
forming a better gas seal. The length of the foam would keep it from
wobbling. As long as the foam was a loose fit, there would be little
added friction. I never got around to building a conical projectile
and just dumped the tennis ball on top of the foam forming a sabot.

As I recall, we got about 60 ft with 50 lbs pressure using only the
tennis ball, and about 90 ft at 50 lbs using the foam Minie Ball.
Videos of the trajectory showed that the air resistance of the tennis
ball was only a little better than if it had been dragging a
parachute. End of flight droop was severe. A better aerodynamic
shape would certainly have been a major improvement. However, I never
tried.

It would also be fairly easy to add spin stabilization, but that would
require a one piece conical projectile.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Antenna Launcher
 

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 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.

Antenna Launcher
 

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

Antenna Launcher
 

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

Antenna Launcher
 

"John Ferrell" wrote in message
...
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

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