Friday, April 3, 2020

Up a tree

Being confined to home during the whole week - working remote through video links - I was looking for an outdoor activity. I decided to do some testing on my various options of launching wire antennas in a tree. Being able to deploy an antenna at a decent height without a mast increases the options for effective activities /P. 
In my little test this Sunday I used two different weights and my slingshot (by EZ Hang).

When I started looking for ways to get a wire up a tree I tried various objects and lines. I found out quickly that it is important that the wire is smooth - so fishing line or decoration line (used in shop windows for example) is the way to go.

Decoration and fishing line

As to the object to throw you need something that is easy to handle, smooth / round (so it glides through the branches) and a convenient throwing weight. Regarding the weight you are looking for a sweet spot: heavier and it will get difficult to throw high, lighter and the object will not return your line back to earth but just keep on dangling somewhere high up in the tree. In that situation you are left with tugging the line hoping the object continues its descent but in my experience you might just as well cause the object to swing around the nearest branch - leaving it behind for eternity. 

I started out with a ball as throwing object. Trying different types I settled on a field hockey ball. The reason being that it fits my hand perfectly and the weight is around the sweet spot (150gr) - not too heavy but generally enough to bring the line back down. Just drill a hole through the middle and away you go.

The ball is kind of large though so not so practical to carry around. Later on I started using fishing sinkers, settling on the heaviest one I could find (90gr). 

Throwing weights: hockey ball and fishing sinker

I tried both and measured the height I could get a line up. Of course it is slightly unscientific as I used only one tree in this experiment - so not all heights were achievable only specific branch heights. It turns out I can throw the fishing weight just a bit higher than the ball. A few tries brought it up to 12 meters / 40 feet. A decent height for a wire antenna on the higher bands.

EZ Hang slingshot

Then I turned to my slingshot. I have been struggling with it in the past, getting the line stuck in the reel or not having the ball come down from the tree (losing a lot of line).

After a few tries I did manage to shoot the provided metal ball a nice way up and through the tree reaching a height of 25m. I think I can shoot it higher than that if I give it a bit more practice. That is a good height even for wire antennas on the lower bands.

The EZ hang standard weight - a 25gr canon ball

The main weakness to me is that the weight of the standard ball is too low to be sure it comes down from a tree with a lot of branches (let alone leaves). So the next thing I will do is test this out with a few different weights. I also have to replace the line as it has become too short after losing parts of it in the past (stuck in trees).

Will share more experiences in the future.


  1. Hi, Lars,
    it was interesting to read about your exercises.

    Relatively long time (only RFF activations are 55, and, I suppose, more than a hundred times in total) I have been lifting my antenna onto tree limbs, and from my own experience I can say that in the vast majority of cases the available height is limited only by the suitable tree limb presence. A fishing lead sinker weighing 1–1.1/2 OZ can be easily let off with an ordinary slingshot to a height of 30–40 meters or even more. The sinker is rarely stuck in branches. I can remember the loss of only three sinkers for this reason — the smaller the sinker size, the easier it overcomes the dense limb interweaving in the tree crown. And only once did the sinker fail to pull the fishing line down for a ridiculous reason — due to the frequent use in pine forests, the fishing line was covered (stained) with pine resin, so the friction coefficient became unacceptably high and the sinker's weight become not enough. It has been hanging on that tree about 10 meters above the ground for a couple of years.

    Now I use 1 OZ teardrop-shaped lead sinkers, 0.25 mm fluorocarbon fishing line (reduced friction), an ordinary slingshot, and a closed-spool inertialess Chinese fishing reel. With rare exceptions it is possible to throw the line through the desired tree limb already in the first attempt.

    Let off the sinker almost vertically, being almost just under the branch (be careful) — a too acclivous trajectory will lead to the searching of your sinker very far from the place of the shot, fishing line may be not enough to cover crowns of few trees, and then the rope will also be not enough. Moreover, more limbs — higher friction coefficient and less sinker's ability to pull fishing line down.

    Check the cleanliness of the fishing line more often if you use it on conifers. Be ready to lose sinkers — take a few spare ones.

    73! Vit, RN3ANT

    1. Thanks for the information Vit. Good addition to the post.
      Last weekend I bought some .25mm fluorescent line so the same LINE of thought ;)
      I also bought slightly heavier sinkers - 1.75 Oz - to see if this helps getting the line down in all cases. Maybe this line has less friction than the original line but it might also be friction in the spincast reel. Will see how this works in the coming weeks.
      Good tip about the pine resin. Might happen here as well.
      73, Lars / PH0NO

    2. Hi, Lars.
      I meant non fluorescent, but fluoroCARBON fishing line. It's most expected advantage for me is protect against pine resin (similar to non-stick teflon in cookware or fluoroplastic in plain bearing). Less friction in the reel is not so important. While I still can't say how justified these expectations are. I think, we can neglect the friction in the spincast reel (thanks, now I know what this type of reel is named in English! LOL). It certainly exists comparing to the spinning reel, but the ease of use of the spincast reel is much more than covers this slight friction.

      The vast majority of forests in our latitudes and to the north are coniferous. Resistance to pollution of fishing line with pine resin is very important for me.

      I did not meet this issue while using the spinning reel and losing a lot of fishing line (it often dropped free turns off the spool, clung to the hand, to the slingshot, to the reel itself, etc.), so it often broke off and had to be replaced more often than got dirty with pine resin. These inconveniences disappeared with the change to the spincast reel, the fishing line began to work much longer, and this pine resin dirty, which I had not even expected before, appeared itself.

      73! Vit

    3. Hi Vit, OK I bought fluorescent line. It stands out quite well.
      We have a lot of different trees out here but not too many pines so I think I will be able to avoid them.
      Trying yesterday I found that there is a maximum with the current slingshot that I think has to do with the rubber and not so much the weight of the sinkers or the friction of the system. I tried a heavier sinker this time and it worked well => next blog post.
      73, Lars