Throwing stuff at the trees again...

It must be spring.

That would explain why I'm throwing things at the trees again. Sure, I'm actually trying to aim tethered projectiles over trees but these shots are turning out to be the exception rather than the rule. This evening, I left work a little early to see if I could place a line in a tall pine. This tree stands with a cluster of others at the south edge of my backyard and makes a nice vertex for a new, 80-meter, horizontal loop antenna that I want to raise. There's a relatively short, optimal period in the spring -- between when it gets warm enough to work outside but not so warm that the ground turns muddy or the leaves sprout and obstruct my aim -- for stringing wire antennas in my yard. That would be now.

Last year, I spent a couple muddy days placing ropes over exactly the right branches in a tall elm. Those ropes were meant to raise a vertical wire antenna and maybe a dipole running NW/SE. To place those ropes I used a slingshot/fishing reel combination I made the year before to shoot fishing line skyward. During that exercise, I nearly chipped a front tooth when the line snagged and the weight careened back into my face (Yet another reason why I always wear safety glasses when doing this stuff -- I face shield wouldn't have been a bad idea, either). Only earned a thick lip that time.

The trouble with the monofilament line/sinker combination last spring was that the bark was damp and soft. The line dug into the branches, generating enough friction to prevent the sinker from pulling the rest of the line to ground. Fortunately, no sinkers got stuck in the tree to become nasty little surprises in the future [velocity = Sqrt(2*height*g) = ouch!]. Another downside to the slingshot combo was that the sinkers occasionally "got away", i.e. broke from the line, sailing off after launch and embedding into the ground upon impact. This is why I chose steel sinkers. Over a couple seasons, I've lost so many that if they'd have been made of lead, the backyard would qualify as a Superfund toxic waste site. On my last shot of the season, an errant weight almost landed in a neighbor's lawn. I don't do this when people are outside, but I decided "the heck with it" and put the little demon away.

In any case, after a couple afternoons the lines were perfectly placed. So... It was a pity that the old tree finally succumbed to Dutch Elm disease that summer. At least the tree removal company retrieved all my rope after they chopped up the tree.

The bright side to $1400 worth of tree removal: 1) Less leaves to rake. 2) A new gap for one leg of a horizontal loop.

Back to now...
I find that pines are easy... well, kinda easy. Their limbs are 'bushy' and I don't even try to put a line over a particular branch. That would be futile. I just aim over the their crowns and the rope always finds something to hang over. This year, my rope launcher is a tethered tennis ball thrown by a ball flinger (of the type used by dog owners when they don't want to pick up saliva-drenched tennis balls by hand), which provides a tremendous mechanical advantage for throwing. A tennis ball doesn't have enough mass to pull rope down so I cut a small slit in the ball and filled it with pea gravel. Also, I slipped a steel sinker through the slit and left the weight's eye outside for attaching a string through a steel leader. The fit is tight enough to keep the ball attached to the line during a throw but sufficiently loose so that if the ball snags in a tree, a hard tug on the line will pull the sinker out and let the ball drop. The ball is also pretty safe -- It doesn't feel great to get hit by it but the impact won't damage anyone. The ball/flinger combo worked pretty well when the attached nylon line was carefully pre-arranged on the ground to avoid snags. I could toss the line over 50 feet into the air and sometimes even in the right direction. It never stuck in the tree and always had enough mass to pull the line over branches to the ground. If the ball went over the wrong branch, it was simple enough to detach the ball and pull the line back. It took about a half-dozen tries but one shot finally sailed right over the tree's crown.

Nice. One thing worked today.

Anyway, about pines being kinda easy...
Most of the time, the launched line drapes over a lot of branches. That's partly good. I want one end of the rope to lie on the outside of the pine's branches. That's the end that will hold the antenna's corner. But the rope's other end I'd prefer to run down the inside of the tree. It's neater and easier to adjust -- and this is particularly important when that end of the rope drapes over a second, co-mingled tree that is technically (OK, *absolutely*) in a neighbor's yard. One strategy for dropping a line near the center of the tree is to tie one end of the rope to a weight, pull that end back up along the outside of the tree almost to the highest branch, and then let the weight drop down through the tree. Ideally, the weight drops the line closer to the tree's core. Unfortunately, another downside to pines is that a line running across a bunch of branches and pine sap has a lot of friction. Also, the branch density near the tops of pines tends to be thick. Unfortunately, this time the friction was too great. It was no problem to raise the weight, but it would never drop down through the canopy -- Too much "grab" on the line.

Switch to option two: Tie a pulley in the middle of the line and run a second line through the pulley. One end of the line through the pulley is strapped to a really heavy weight. The idea is to pull the pulley and weight as high into the tree as possible and then release the weight down the center of the tree. This is a two-person operation. With my wife (new ham: KO1RGI), pulling from the far side, I kept the weight near the top of the pulley as it moved up the tree. After it reached a spot close to the top, I let the weight descend. The pulley has little friction and so the full force of the weight can be used to crash through the branches. After the weight touched down, I knotted the other end of its line to keep it from passing through the pulley and then tugged the rest of the contraption (pulley plus the free end of the original line) through the tree and down the trunk. It is not perfectly placed but it is very close.

Three more corner lines to place...

(Note: The photograph is from here)