by Joe Everhart, N2CX
Here are two excerpts from last year's Dayton "FDIM 97" presentation and paper I gave last year entitled "Portable Antenna Success". Sure hope you find them useful!
How to Put up a Portable Antenna
Putting up wire antennas is always a fun proposition. Sometimes it is fun for the participants and often fun for on-lookers. There are at least as many methods as there are folks putting up antennas. The following is a short discussion of methods mentioned on the QRP-L mail list. Trees will be assumed to be the temporary mast of choice
First of all you need an antenna! But then you knew that. And no matter what kind of support or antenna launching method employed you need some support line. Two popular types of line are nylon parachute harness cord and nylon seine twine. Both are strong, weatherproof and reusable. Harness cord is available from various military surplus sources and seine twine is very inexpensive at the ubiquitous hardware mega-stores. For temporary installations, cotton line is usable, but it doesn't hold up like nylon or other synthetic lines. You may be tempted to use fishing line, but if you do, be very careful. It is nearly invisible to birds and other wildlife so it may pose a hazard to them while in use. And whatever you do with *any* line, don't leave it behind as it will not degrade over time and may remain a hazard for many years. Next are the methods, which fall in several categories .
First are the armstrong methods. They involve attaching a weight of some sort to the end of an antenna line and pitching it in some manner over the antenna support. Weights used by various folks have included fishing weights, assorted hand tools (many of which remain tangled in tree limbs - beware in the forest!), rocks, twigs, penknives, solid rubber balls, tennis balls and nearly anything else that a frustrated launcher might have within arm's length. Launching methods with the weights include the overhand toss, the underhand toss and the popular South American gaucho bolas toss.
The latter is my favorite. To achieve this, you take the weight in one hand, then let out several feet of line so that the weight hangs down. Next, you spin line with the weight describing a circle. When you release the line, the weight will go off tangentially and, if you are extremely lucky, it may even go up in the direction of the antenna support. And the first time it does, I usually find that the extra line I left on the ground to soar skyward has wrapped itself around my leg while the weight has reversed direction and is hurtling back toward me. Of course when I try to avoid the incoming missile, my encumbered legs prevent quick escape so I trip and fall *before* the weight homes in on my coconut! To minimize damage to property and bystanders, I use a fishing weight slid inside a slit tennis ball. The ball makes for a soft landing and its fluorescent color makes it easier to find when it gets away.
There are several other launching strategies that are in keeping with the outdoors theme of portable QRP'ing. They are the Robin Hood, the Isaac Walton and the David and Goliath maneuvers.
As you may have guessed, the Sherwood Forest trick involves using a bow and arrow. Impressive heights and pin-point accuracy can be demonstrated by a skilled archer. Most of us are lucky to get the line somewhere near the right tree. Two important precautions are imperative. First, make sure that you work as a team with someone to "downrange" who will warn passers by to evacuate the area watch to see where the arrow lands. (Remember the second part of "I shot an arrow into the air...?) Second, make sure that the line is firmly attached to the arrow. That will limit its travel when it overshoots the mark.
Yes, the Isaac Walton method uses a fly-casting rod. It is amazing to see how well a talented caster can place a weighted line accurately in a tree. On the other hand, it isn't for the bashful. If you try it you *will* be questioned about your activities. Doug, KI6DS informed a curious neighbor that he was "tree-fishing!"
David of Goliath fame had nothing on modern-day sling-shot users. In most states, you can zip over to your local Walmart and pick up an inexpensive "Wrist Rocket." (In enlightened New Jersey you have to get a permit for them same as for a 38 Special!) The Wrist Rocket can be set up with a fishing reel to pay out line that is launched at the end of a one-ounce fishing weight.
One of the funniest tongue-in-cheek launching schemes was "recommended" on QRP-L. Someone was describing the nitrogen pressure cylinders sometimes seen at the base of telephone poles. In a fit of whimsey, another guy suggested the possibility of inverting the cylinder, tying on an antenna line, then breaking its neck with a hammer to rocket the line over a tree. After several minutes of contemplation, he posted another message saying "Don't do it! I was just kidding!" He probably had visions of someone actually trying it with disastrous results and hitting him up with a monstrous law suit!
Safety and Responsibility
When you are putting up antennas and operating portable, please keep safety and responsibility in mind. Don't put up antennas so that they are a hazard to yourself, others around who might no see a low-hanging wire, or wildlife who are allowing you to share their home. Other hikers or campers will *not* expect wires to be strung around in a natural setting so don't put them where they can be a problem. And particularly in campgrounds, watch where you put up antennas. Many I've visited definitely did not meet local electrical codes so I never knew where they might have strung up their ac distribution wiring.
Always keep in mind what a Boy Scout leader impressed on a bunch of us "city kids" long ago. Don't destroy any trees or shrubbery and don't leave any man-made stuff behind. He told us that considerate campers leave a campsite in better shape than when they first came.