Aerials and Trees

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From time to time we all need to get wires or lines over trees to support aerials. With a small tree of say 5-7 metres high it is quite easy just to throw a weighted line over the top. But what if the tree is larger?

Over the years I have tried quite a few ways but the best by far has been the use of a catapult - suggested to me by Dave G3YXM who also uses a bow and arrow! Catapults can be bought from fishing shops and are used to throw ground bait. Look for a high power model and for maximum accuracy and power, choose one with an arm brace (see picture below). But don't leave the fishing shop just yet as you will need some more things. First get a cheap casting reel. They are often available for about 5. This needs to be fastened on to the catapult. I used some cable ties. The casting reel ensures that the line flows freely. Laying the line on the ground generally fails as it gets caught or tangled. For line, you need to choose something thin and light - this line will not be used to support the aerial, it is just to get it over the tree. Use 12-15 pound breaking-strain monofilament. You will also need a weight to fire. I use a 2 oz sinker. I paint them orange to make them easier to see in trees! Tie the weight on to the line using the special knot that works with monofilament (called a blood knot I think). This knot is described in fishing books. I have also had success with a figure-of-eight knot.

Now you are all set. Safety must be your first consideration. Make sure that the area around the tree is clear of any people, animals, overhead electricity cables and anything else that could either endanger you or could be in danger from your efforts. Fire the weight aiming well clear of the top of the tree, an angle of between 45 degrees and 60 degrees to the horizontal seems best. If all is well the line should pay out cleanly but generally the weight will not reach the ground. Gently pull on the line several times, letting the weight drop further each time. Then go and see if you can find it. The paint helps here! If you fail to get it in the right place, you have two choices, either cut the line and let the weight drop or try to pull it back. If you do try to pull it back be very careful as the weight can easily fly out of the tree in your direction as you pull on the stretchy monofilament.

If all is well and the weight has reached the ground in the right spot, then cut the weight off the line and tie on a thicker line that will be used to support the aerial. I use 40 pound or 100 pound monofilament. Pull this line back through the tree, tie on the aerial, pull it up and you're on the air. I have used this method successfully with trees up to 90 feet tall (27 metres).

Catapult.jpg (90008 bytes)

The G3CWI Catapult in action

 

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