http://www.antennalaunchers.com/antlaunching.html
Pneumatic Antenna Launching Systems
Pneumatic Antenna Deployment Systems
[TBL-U37A-0]
My First Pneumatic Antenna Launcher - They are much smaller now, see
below
News and Updates
* We keep the Latest news Here
* CSV19 - Constructing a Compact Low Cost Sprinkler Valve Antenna
Launcher
* DFTV19 - The Darn Fast Turbo Valve Antenna Launcher
* The Rest of the (Antenna Launching) Story
* A Tale of Two (Compact) Antenna Launchers
* QE19 - Constructing a Compact Quick Exhaust Valve Antenna
Launcher
* Visit the NEW Antenna Launching Discussion List
* Launcher Modelling Results
* TBL Launcher Article (published in QRP Quarterly, pdf)
* Launcher Performance Data Measurements
* Eric's revised Trident Launcher
FAQ - Frequently Asked Questions
What is Pneumatic Antenna Launching?
Pneumatically Powered (Tennis Ball) Antenna Launching. Pneumatic Line
launching is perhaps a more apt description. First we need a line in
the trees, then we can pull up an antenna, which in most cases is a
long piece of wire. In the launcher pictured above a Tennis Ball is
propelled by compressed air, towing a fishing line over the tree.
Then we pull up nylon mason twine with the fishline, and finally a
wire or heavier line as needed.
Why does anyone need to Launch an Antenna?
It is often more convenient to use existing trees than to erect
supports for wire or beam antennas, especially when these antennas
are required for temporary or emergency field use. We set up antennas
for disasters and drills, camping and contests, practice and fun.
With all the applications for Homeland Security there are many
potential uses for rapid deployment. If you have a need to quickly
set up antennas in various field situations, or you have some really
nice trees in your backyard, you may have a use for Antenna
Launching.
What is a Pneumatic Antenna Launcher?
It is a very simple system that uses the energy in a pressurized
volume of gas (generally air), a valve to release the gas, and a
projectile (tennis ball) in a tube that is accelerated by the
expanding gas giving it the requisite velocity to pull a light line
over the tree.
Why not use a ... (Slingshot, Bow, Rock, Stick, Crescent wrench,
Blackpowder Cannon, 12 Gauge)?
We have used many different systems since the 70's to put lines up
into trees. Each system has advantages and disadvantages. Throwing an
object over a limb is the easiest, but will not reach very high, and
there is a significant chance of getting the object stuck. Slingshots
reach higher, and Bows reach higher yet. The main problem with all
these systems is the projectile. A lead sinker, arrow or crescent
wrench can do a lot of damage if it lands in the wrong place. If you
are putting a line over a tree in your yard, there are often local
ordinances against using slingshots and bows. What is needed is a
really safe projectile, and a means for getting it over the tree
precisely for maximum safety and effectiveness. If you have a really
tall tree, then a Tennis Ball Launcher will allow you to go higher
than most slingshots or bows. Even a small Pneumatic Tennis Ball
launcher can reach up more than 150 feet, and it is possible to go
much higher with the more effective models.
No, We did not try the Black Powder Cannon. I recall seeing an
article about that in 73 magazine years ago. I think we've found a
safer solution... And the 12 gauge - we've heard details, but we
didn't and don't you try that one either...
My slingshot/bow works fine, why consider a Pneumatic Launcher?
You might consider a Pneumatic Launcher if you are interested in more
Performance or greater Safety. Slingshots and Bows work, but
Pneumatics work better. Eric's big launcher can put a tennis ball up
over 600 feet high (with no line). The small CSV19 reaches up to 200
feet towing line, and the dimunitive CSV17 goes over 150 feet towing
line. These launchers are 19 and 17 inches long, respectively, and
the heights are measured length of line pulled out. Add about 9 or 10
feet to those numbers to get the apogee, since the reel is about 10
feet off the ground when launching upwards. You can make launchers go
higher, and we have, but the availability of trees that tall and
feedlines that long makes it rarely useful. So I scaled the
pneumatics back to the smaller sizes. Also be very careful with the
slingshot and bow, there are many injuries each year, especially with
the slingshots.
If you are going to put up an antenna in the backyard the tennis ball
is a lot safer than a lead sinker, and much easier to explain to your
neighbor.
Why use a Tennis Ball?
There are three primary reasons to use Tennis Balls. Safety, Safety
and finally, Safety. I have read of so many accidents with slingshots
each year that I cannot recommend them. A lead sinker flying through
the air is potentially an accident waiting to happen. They bounce off
the tree, the line snags and the sinker returns on the line rebound,
or they get hung up and come sizzling down when the line is pulled,
potentially at higher velocity than even the slingshot can impart.
The slingshot is not the problem, the projectile is the problem!
A Tennis ball is inherently a fairly safe projectile. They are big so
they slow down quickly, limiting the distance they will travel and
the velocity they impact with. They are not hard, so they tend to do
little damage when they land. It is something familiar so people know
what to expect. It is big enough to see fairly well. They are
available and inexpensive.
How High will these Launchers reach?
130 to 200 feet of height is easily attained with a Pneumatic Tennis
Ball Antenna Launcher while towing a 50 pound test fishing line. It
is possible to go much higher with the more efficient or larger
launchers, but we have not found suitable antenna trees much over 130
feet tall. So we consider 150 feet to be about optimal.
Are there other uses for these Launchers?
We have seen a number of other applications for these launchers:
* Cutting high tree branches using a pull-chain saw
* Deploying Safety Lines for roof, tree or tower work
* Putting climbing lines in place for treetop canopies
* Training dogs for fetching after a mild report
* Putting a temporary wire antenna part way up a tower without
climbing
* Putting a line across a pond
* Fishing - Casting far out in the surf or lake
Are these Launchers Dangerous?
If you've played or watched tennis you know that the serve is
(usually) one of the harder hit strokes in tennis. Well, a good serve
has more velocity than is required for launching a tennis ball over
most tall trees. The ball slows down quickly, and on the far side of
the tree (towing the fishing line) it comes down very slowly. Our
launchers use velocities lower than a fast serve.
The simplest material for building an Antenna Launcher is Schedule 40
pressure rated PVC. This material is designed for working pressures
in excess of 200 pounds per square inch, and the pressures we use are
up to 60 or 80 psi. So while the pressures are within design
parameters, the manufacturers of PVC pipe and fittings RECOMMEND
AGAINST its use with COMPRESSED AIR. If PVC containing compressed air
is fractured, it may result in high velocity PVC shrapnel. So avoid
breaking it while it is pressurized, and wear safety glasses when
using launchers or any power tool. Low and high temperatures make PVC
brittle or soft so launchers should not be used in extreme
temperatures Note that in many years of making and using these
launchers we have seen a few broken in various ways and never have
wee seen any shrapnel. The low volume and pressure we use is not
likely to produce any.
Are these Launchers Regulated? Aren't they Illegal??
Here in the US the Federal BATF (Bureau of Alcohol, Tobacco and
Firearms) has ruled that pneumatic launchers are NOT firearms. Some
Municipalities have regulations that may affect the use or ownership
of Launchers. Such rules are not common, and the ones that do exist
usually focus on combustion type launchers rather than pneumatics.
Check with the local authorities to be sure. Note that slingshots and
bows are generally illegal to use in residential areas, parks,
campgrounds, etc. Here is the letter from the US BATF on the subject
How much does a Pneumatic Antenna Launcher cost?
The materials for a launcher cost between anywhere from about $60 to
$100 or more, plus a fishing reel, some line and a few tennis balls.
If you have leftover parts from a lawn sprinkler project it may be
much less... Launcher Kits are available starting at about $100, see
the Online Catalog.
How hard is it to build a Launcher?
It depends on the model, and it ranges from fairly simple to quite
complex. If you can cut and glue PVC and thread pipe fittings
together you can build the simple models. Some require drilling and
tapping a hole or two in the plastic, some need a little soldering.
Kits are available for some models, so the hard parts are already
done. The time required varies from a few hours on up. The more
complex designs may require a friend with a lathe to machine some
PVC. Generally speaking, as size/weight/cost go up, so does
performance. A low performance design might require 80 psi to launch
150 feet high, whereas a higher performance design might do the same
job at 25 psi. Choose a design that matches your construction
ability, budget, size requirements and the trees you need to launch
over.
What kind of Pneumatic Antenna Launcher should I build?
Eric (WD6CMU) and I (Alan WB6ZQZ) have been experimenting with Tennis
Ball Launchers since 2002. We have built nearly a dozen different
models, and I have written software that analyzes and predicts
performance. A couple had insufficient performance, and some others
had excess performance. (Excess performance is not always a problem
as it does allow operating at lower pressures, but it may mean that
the Launcher is larger and heavier than it needs to be.) We seem to
be settling on about sixteen inches of barrel length, a 1" sprinkler
or 3/4" pneumatic valve, and approximately 60 to 100 cubic inches of
air storage. This produces a launcher that weighs in the neighborhood
of five to seven pounds, and produces sufficient performance at about
40 to 60 psi for most launches. The barrel material is 2.5" schedule
40 PVC, into which a tennis ball fits very snugly, or 2.5" SDR21 PVC
into they fit nearly perfectly.
To get specific I will mention some of our models,
* The CSV19 and its smaller sibling the CSV17 are fairly simple to
build, and are available in kit form. This may be the best
compromise and we provide the most detailed information on
building this unit, as well as partial and full kits of prepared
parts on our Online Order Page.
* The U37 and DU36 U valve models are simple to build but are a bit
larger than some of the newer designs. The original QRP Quarterly
article describes building the first (electric) version of this
model (U37) in some detail and the pdf is available here. It was
designed to fit between the wheel wells of a Toyota 4Runner and
is 37" long. I later modified this to pneumatic triggering and it
became the DU36. It will not fit in the Rubbermaid(tm) tote boxes
that we use for our newer designs.
* The Field Day 2003 special is not hard to build and does not
require exotic tools. It is a bit larger and heavier and more
expensive than the newer smaller models. There are some pictures
and info here for the Field Day 2003 Special. It also will not
fit in the Rubbermaid tote due to the overall length.
* The QE19 Quick Exhaust Valve design is the simplest to build and
is fairly lightweight and small but requires a bit more air
pressure to operate. The 3/4" Quick Exhaust valve limits the
airflow somewhat, but it does reach up to about 150 feet of
height at 70 psi, and it can safely take 100 psi. Due to all the
brass parts the cost is somewhat higher as well, but there is no
need to bore, drill or tap PVC so construction is straightforward
and few tools are required.
* Eric's Trident design utilizing the soda bottle pressure chamber
is the lightest but has some difficult to make threads, and the
pressure needs to be kept low to protect the chamber.
* The DV19 Dual Valve is complicated to build but does not require
exotic tools. It has very high performance. Due to the high parts
count the cost is on the high side and the weight is high also.
It still fits in the Rubbermaid tote, but nearly fills it up. The
high performance allows reaching tall heights at low air
pressures. I do not provide detailed instructions on building it,
but there are several photos in the Tale of Two Launchers page.
* The DFTV19 Turbo Valve requires a lathe to make the parts. It
also provides very high performance. Due to the custom made parts
the weight is quite low and the cost is low but the effort
required is high. A drawing and some photos are available there
for those who have access to a lathe..
* The Spud Tech TB500LP is commercially available. It is a bit
larger and heavier than our current models but should do the job.
[PADS01]
The PADS Pneumatic Antenna Deployment System with Accessories
What is a Pneumatic Antenna Deployment System?
This is the name for the Launcher-in-a-Toolcase shown above. The
CSV17 launcher fits nicely into this hard case. It may be small but
has been able to reach over 150 feet in height. The PADS launcher and
hard case are available on the order page. Also shown are a pair of
Twine Reels containing 500 feet of nylon twine. They are available in
270 foot lengths as well. The grey cylinder near the bottom center of
the photo is a bicycle type CO[2] tire inflator. It can be used with
a number of different capacity CO[2] cylinders. Using the low-cost 12
gram cylinders produces enough pressure for one good launch per
cylinder. Also in this case, but not visible is a 12 oz Paintball CO
[2] cylinder stored inside the barrel, along with two tennis balls.
The CO[2] pressure regulator is behind the right end of the ramrod.
There are a total of six tennis balls in this photo, two hidden in
the barrel and one hidden inside the reel on the lower left. The
Mini-Coaxial reel on the lower left is a special reel made for this
launcher to fit in the case. It is a scaled-down Zip-type reel with
about a one foot circumference. Just behind the launcher's trigger is
a bag of 12 gram CO[2] cylinders for the bicycle inflator. See the
PADS Web Page.
What about a Ball-valve type launcher?
The simplest pneumatic launcher is a pressure storage chamber, a
barrel, and a ball valve in between. These are not particularly
suitable for antenna launching because the performance is dependent
on how quickly the valve is opened. Additionally, opening the valve
manually disturbs the aim, so it will be difficult to make it go
where desired.
What about a Combustion powered launcher?
Combustion type launchers use lighter fluid, spray deoderant, propane
or some other fuel in a closed pipe chamber behind a projectile with
an ignition source to light it off. In addition to some safety
concerns, combusion launchers may produce somewhat inconsistent
shot-to-shot performance, which makes them difficult to use as a
serious Antenna Launching tool. They also misfire occasionally,
require cleaning and maintenance and are more often regulated than
pneumatic systems. Let's not use them for Antenna work!
How Small and Light can an Effective Pneumatic Antenna Launcher be?
First, I'll define 'effective' as any launcher that can toss a 4
ounce tennis ball to a height of at least 150 feet towing a fishing
line. That is pretty adequate for our purposes.
The smallest launcher that meets this criterion that we have built is
the CSV17 shown above in the PADS kit. This is a 17 inch long model.
The popular CSV19 Compact Low Cost Sprinkler Valve Antenna Launcher
and the Quick Exhaust Valve Launcher are only a little larger. At
about six pounds, these are small enough to fit into a Rubbermaid
tote box, or less than 19 inches in length. There is plenty of room
left in the tote box for line, antennas, feedline, and other
equipment.
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[csv19]
The CSV19 Compact Low Cost Sprinkler Valve Antenna Launcher is
assembled from plumbing parts most of which are available from local
plumbing or home improvement stores for under $100. Some machining is
required to make them fit together as shown above. The dark grey
barrel is SDR21. Schedule 40 also works, but the ball is very tight.
SDR21 fits better but is harder to find. This is the lowest cost
simple to construct launcher I have designed (the CSV17 variant is a
little easier and even less costly). The link above has fairly
complete construction instructions. The collection shown above is
shown complete with Saunders Zip Reel with yellow Spectra type
synthetic line, and a couple of prepared Tennis Balls sitting on a
Rubbermaid 10 gallon tote. The gear fits into the tote with room to
spare.
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QE19 Photo
The QE19 Quick Exhaust Valve Launcher is the smallest and lightest of
my launchers. It is based on an industrial quick-exhaust air valve
(the silver item in the photo, linked above). This is an easy
launcher to homebrew, but due to the industrial and brass parts costs
somewhat more than the model above, about $100. The link above has
construction information. This launcher is sitting on top of one of
the Rubbermaid (tm) 10 gallon tote boxes that I use to carry
equipment to field. There is room for lots of gear in there in
addition to the launcher.
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The lightest launcher we've done to date for Tennis Ball Antenna Line
Launching is Eric's Trident which uses soda bottles for the air
pressure reservoir and weighs a litte less than five pounds. Eric
also came up with a nice mount for an archery fishing line reel that
fits around the barrel and feeds line very smoothly. Check out Eric's
website at wd6cmu.antennalaunchers.com for his Saunder's Zip-reel
mount and Trident Launcher.
[CRW_2590_RT16_800]
The Launcher on the left is the Quick Exhaust model, here shown in
the 28 inch configuration with a spinning reel mounted just below the
forward end of the barrel (hard to see against the foliage in this
photo). This photo was taken before it was shortened to the 19"
version shown above. The two launchers in the photo were used on
Field Day 2003 to put up numerous antennas. Field Day is an Amateur
Radio 'Emergency Drill' essentially, setting up and operating in
field conditions for a couple of days. It is a lot of fun and a good
test of our equipment and technique, both radio and Antenna
Launching.
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More Pneumatic Antenna Launcher Examples
High Performance in a compact package: DV19
This model packs a pair of one inch sprinkler valves in to a
Rubbermaid sized tote package. It doesn't take much pressure for this
unit to reach 150 feet of height! Building this is quite a challenge
with all the plumbing parts packed in tight. There are the two 1"
sprinkler valves, a quick exhaust valve trigger, two check valves, a
paddle trigger valve, and some specially adapted (shortened) PVC
fittings. It was made with fairly minimal tools - a drill press and a
belt sander, plus a radial arm saw. None of these tools are
absolutely required - this design can be made with hand tools. It is
a bit heavy, around 10 pounds. As shown below it includes the
Saunders Zip Reel and a removable barrel extension that improves the
efficiency of the launcher. For more info on this launcher see A Tale
of Two (Compact) Launchers.
DV19 Photo
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Ultra Performance in a Compact Package: DFTV19
This six pound model packs a tremendous capability in a very
lightweight package. It fits in the Rubbermaid containers as well.
The Darn Fast Turbo Valve is a 1.2" ported homemade piston valve with
a self-venting and turbo actuation features that make it low cost,
light weight, and incredibly effective. The only disadvantage to this
design is the requirement for precision machined parts in the valve.
I purchased a small lathe (www.Grizzly.com) and made them with no
prior machine shop experience, so it isn't all that hard. More info
is available in the The DFTV Story.
DFTV19 Photo
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More Examples can be found via links in the "More Information"
section below.
How is Launch Pressure developed?
The pressures and volumes involved are similar to a bicycle tire, so
automotive or bicycle air pumps are just about right. The portable 12
volt electric ones are great. They run from a car battery or are even
more portable with a Gel Cell. Hand or foot pumps work well also, and
have the benefit of a good aerobic workout. Some folks use CO[2]
systems which are very convenient at greater cost. I recently have
been testing two CO[2] systems - a Paintball cylinder and regulator,
and a Bicycle tire filler using 12 gram cylinders. CO[2] systems cost
a bit more to own and operate, but they are pretty amazingly
effective and fast.
I tested a 6 gallon compressed air tank recently and starting with
100 to 110 psi was able to get about 15 shots at 50 psi from it with
the CSV19 launcher. The smaller chambers on the CSV17 and QE19 would
get even more launches per fill.
Here is a portable battery powered filling station similar to the one
I have. This has become a favorite for charging the launcher. It
takes about one minute. Mine has a 12 volt 17 amp gel battery and a
compressor and was under 50 bucks at Harbor Freight tools. After you
launch the antenna you can hook up to the 12 volt gel battery and run
the station!
Jumpstart Box Photo
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Detailed Antenna Launcher Construction Articles
The Compact Sprinkler Valve and Quick Exhaust Valve models have
fairly construction details on their web pages. I wrote a complete
construction article on the TBL-U37 pictured above (lead-in photo and
electric actuated above). It was published in the QRP Quarterly
magazine, Spring 2003. A pdf version is available here. Note that
changing to pneumatic actuation makes a large performance improvement
in this launcher. A similar launcher that has good performance is the
Field Day Special. Information on this model is available on the
Modelling page.
Can I buy an Antenna Launcher already built?
We supply plans and kits and also build launchers, see www.AKBeng.com
for details.
SpudGun Technology builds launchers: The SpudGun Technology Center.
They sell components and complete units (without reels or launch
balls). Look under the "Launchers, Low Power Pneumatic" links. UPDATE
- the SpudTech business is open again. The TBL500LP with a 24" barrel
and 12" by 3" chamber is about the right performance level.
(Disclaimer - I have not used any of SpudTech's launchers.)
Where can I get More Information about Pneumatic Antenna Launchers?
There is a lot more info on the web. Most of it is not directly
Antenna Launching related, but much can be learned there that is
applicable. If you find the information on this website useful and
have a website of your own, please include a link to this page to
help others find it. If you have related information and want a link
here on my page drop me an email!
* Launcher Development and Production News
* The Rest of the Story (Antenna Launching)
* Visit the Antenna Launching Discussion List
* Constructing a Compact Low Cost Sprinkler Valve Antenna Launcher
* The Pneumatic Antenna Deployment System
* A Tale of Two (Compact) Launchers
* Constructing a Compact Quick Exhaust Valve Antenna Launcher
* The Darn Fast Turbo Valve Antenna Launcher
* Launcher Performance Data (Measured)
* my original Antenna Launcher Article (QRP Quarterly Spring 2003)
* Pneumatic Launcher Calculations
* Eric's Launchers and Reel System
* Eric's Trident Launcher
* Mark's Antenna Launcher
Other Launcher Construction Websites (Not necessarily Antenna
oriented)
* The SpudGun Technology Center has a wealth of info, parts, and
complete units for sale
* Advanced Spuds
Or Search the Web:
The following links perform Google web searches with various
arguments that produce lots of hits for this topic. (We have no
control over the results of these searches).
* Compressed Air Cannon
* Tennis Ball Launcher
* Tennis Ball Cannon
* Pneumatic Cannon
* Spud Gun
* Spudgun
* Spudgun technology
* Spudlaunch
* Backyard ballistics
* Aircannon
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Updated 9/2016