Getting a portable antenna into the top of a high tree can be a real challenge without the right tools.
While a string tied around a small rock is fine for bushes and rooftop sized trees, it won't work for high limbs. On the other hand, a bow and arrow can launch a line over the highest branches. The problem with bows and arrows is that they can cause serious injury or property damaged in the hands of an inexperienced user. Most bows don't fit well inside the average backpack, either.
A better way to get an antenna in the air is with a slingshot and a fishing reel. The HyLaunch -- my name for the antenna launching system described here -- is cheap, accurate and safe when used with caution and common sense.
Best of all, one can be built on a Saturday afternoon using simple hand tools. Here's how.
Parts for the HyLaunch consists of a small slingshot, an inexpensive fishing reel, a couple strips of aluminum, some screws and a bicycle handlebar grip.
Construction consists of little more than bending the aluminum strips to the correct shape and screwing the parts together.
Ideally, the fishing reel should be attached to the slingshot to form an integrated antenna launching system.
The accompanying example (Figure 1) uses two short lengths of 1/4" thick by 1" wide aluminum bar to sandwich the slingshot into a single unit.
The reel support bracket provides a platform on which to mount the reel. The aluminum stock is quite soft and is easily bent using a bench vise to keep the work steady.
The dimensions of the brace and reel support bracket will depend upon the slingshot and fishing reel used. Just remember to provide sufficient clearance between the slingshot handle and fishing reel mount for your fingers. For my version, I found an 18-inch long piece of scrap aluminum at my local hardware store in the "cut off" bin for 50-cents. The reel support bracket used about 10-inches while the brace required about 4-inches.
The brace, slingshot frame and reel support bracket are joined using large sheet metal screws as shown in the photograph. Clamp the assembly together in a vice and drill the holes for the screws through both pieces of aluminum at the same time. Insert the screws from the reel support bracket brace side. Torque them down tightly and cut off any excess protruding through brace.
Temporarily clamp or tape the fishing reel to the reel support bracket and drill two mounting holes. If the reel has a metal mounting foot, use small sheet metal screws to attach the reel to the bracket. As was done with the handle, file off any excess screw length.
If the reel's mounting foot is made of plastic, machine screws and nuts should be used instead.
Finish the assembly by slipping a bicycle handlebar grip over the launcher's handle. If the grip will not slide on easily, heat it up in a pan of hot water to soften the plastic. Just be sure to wear gloves to avoid burns.
The fishing reel shown in the photograph is a Shakespeare, MicroCast model (about $18 at KMart). I have also used the Zebco Model 202 with great success and they cost less than $10. As a bonus, the Zebco reels come pre-spooled with 100 yards of 6-pound test line. I opted for the Shakespeare because it is physically smaller than the Zebco.
The slingshot is manufactured by Crossman and also purchased at KMart for less than $5. It is a low-end model with a frame made of quarter-inch aluminum rod. Although I've not tried it, the "Wrist-Rocket" model might provide better support and control for higher shots.
It is essential that you test the HyLaunch before taking it to the field. Begin by spooling the fishing reel with one or two hundred yards of 4-6 pound test monofilament fishing line. Next, tie a 1-oz. teardrop-shaped fishing weight to the end of the line. Test the reel by alternately releasing a few yards of line and reeling it back in.
Make sure everything works smoothly.
Before you try your first test shot, promise yourself you will always exercise safety and good sense when using this device. Begin by wearing a set of safety goggles, not just once in a while, but every time you shoot.
It is also a good idea to wear a leather glove on your shooting hand in case the lead weight goes astray. Finally, never shoot toward people or personal property. Remind yourself that you are dealing with a tool capable of doing serious damage or harm if misused.
When you're sure your shooting area is clear, select a fairly low limb as a target. Step back a few yards and aim just above the limb. Don't over do it. It doesn't take much pull to lob the sinker over a fairly high branch.
Once you have the line where you want it, allow the lead weight to drop to the ground. Remove the sinker and attach a spool of light weight nylon string to the fishing line. Use the fishing reel to draw the nylon string over the branch.
Next, disconnect the fishing line and use the nylon string to pull a length of polypropylene rope back over the limb. It is the poly line that will be used to support the antenna.
While it may sound complicated at first, it is really quite easy to shoot a line over a high branch using the HyLaunch.
Shooting accuracy improves with practice and higher antennas yield better signals. But don't take my word for it. Try it yourself. You'll be happy you did.
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Bill Jones, KD7S, is a contributing technical editor for The ARS Sojourner living in Sanger, CA.