Throwing antenna woes to the wind

By John Kalotai, N1OLO
Special to The ARS Sojourner

May, 2005

So there you are, walking along, out in the woods looking for the perfect operating position. You come across a stand of mighty oaks but the nearest branch is about 45 feet up. What a great tree from which to hang a antenna! So you whip out your fancy sling shot with the fishing reel attached . All of a sudden out pops your local DEP officer, who says: “Sir, put down the weapon”.

N1OLO: “Huh? But its just a sling shot….”

DEP Cop: “Sir, park rules prohibit the possession of a sling shot in the park.”

N1OLO: “But I want to put up a line in that tree, see I’m a ham operator and ….”

DEP Cop: “Maybe you could train a squirrel to get it up there but you can’t use the sling shot”

OK, he wasn’t quiet that sarcastic. In fact he was really nice but adamant about the sling shot. Rather than confiscate it he let me walk all the way back to my car and put it away.

I now had a dilemma. I found the ideal place to Spartan Sprint. All I had to figure out was how to get my line up there. I tried training a squirrel but it was spring and the lady squirrels proved too much of a distraction. The sling shot was out. A fishing pole would work, but would I need a fishing license? (In Connecticut possession of angling equipment assumes the intent to angle.) I didn’t even want to think about a bow and arrow. I’m sure the conversation would have been interesting if I had a spud gun! What was I to do?

( A few weeks later)
I am career paramedic and I get some interesting assignments. One such interesting assignment was to cover an arborist convention. With competitions including sawing and tree climbing there was a feeling my services might be needed. The first competition I saw was tree climbing. The arborist walked up to an oak, pulled out a smallish bag attached to a yellow line. He stepped back a few paces, swung the line back and forth and then sent the line sailing up the tree and over a crotch about 45 feet up. The weighted line dropped down to the ground like nobody’s business! The next competitor got one up to the 60 foot mark! I’ve got to find out about this!

Arborist conventions are like any other convention. There are vendors there to show and sell all the latest toys. I looked around and found what the tree climbers were using. The salesman explained what I saw was a throw bag and “slick line”.

Throw bags are nylon or vinyl bags filed with steel or lead shot. There is a “D” ring on the top used to attach a light weight line. They are available in weights from 10 to 16 ounces. The slick line is 1/8 inch braided polyethylene rope. It’s called slick line because the polyethylene is very slippery and will easily slide over the bark of a tree. It also resists knotting and fouling.

Great! I bought the bag and line, but how do I use it? The helpful salesman was a former tree climber and gave me a few pointers. First start out by attaching the line to the bag. Because the slick line is so slick it’s difficult to tie some knots. The bowline is a fine knot to use with slick line. Tie the slick line to the “D” ring using a bowline. You will also want to put an overhand knot approximately 18 inches up from the “D” ring.

Next, you will need some type of container to hold your line. There is a commercial stuff bag that attaches to the tree climber’s belt; however, a 3 lb. coffee can will also work. The line is looped into the can. I really liked the stuff sack myself because its easier to carry in my pack, but I do have a kit set up in a can.

To deploy the line, hold the line at the over hand knot you made earlier. This is important! That knot assures you hold the line in the same place every time. When you swing the throw bag and line the arc will always be the same giving you some consistency. Stand facing your target, hold the bag in your dominant hand and set your feet with the foot opposite your dominant hand forward. So, if you are right-handed, the left foot will be forward.

Make sure that your line is not fouled on an object. Standing on the line is also counter productive. Please make sure you don’t have the line running between your legs. Start to swing the line back and forth. On your forward swing release the line near the end of the swing. The release point will vary depending on high an arc you need. This release point is a matter of feel and accuracy comes with practice.

“How far from the tree do I stand?” you may well ask. The higher you want the line to go the further back you will have to stand. Again, judging this distance comes with practice.

After my shift was done I brought my new toy home and started to play. My first throw went wide of my target but the line and weight dropped through the tree easily.

If you miss on the first try you have three choices:
1. pull all 150 feet of the line through the tree and throw again
2. pull the throw bag back up through the tree and back to you
3. live with where the line ended up

I suggest that you pull the line through rather try to pull the weight back through. When the bag does get stuck and you pull on the line the throw bag will inevitably come shooting back at you.

If you do pull the line through the tree don’t be too concerned about stuffing the line back into the can or sack unless you are in some rough terrain. If you are standing on grass or other relatively smooth surface you will be able to simply lay the line out on the ground. I spent the next half hour practicing and getting comfortable with putting the bag where I wanted it to go. After I replaced my downed dipole (that squirrel I was training chewed through the support rope gathering material for a nest for his lady friend) I was ready to go back to the park!

I returned to the park and found my stand of oaks. I launched the line, hit that branch at 45 feet and pulled up an end fed wire using the slick line as the support. I spent the rest of the afternoon playing around on 20 meters and had a great time.

Now for some words of caution:

1. You are throwing 10 to 16 ounces of metal into the air. Make sure you know who and what is down-range. I personally have a cracked windshield to show for my early efforts!

2. Check the area carefully for power lines. Though the polypropylene is non-conductive you can pull wires down. If the line gets sufficiently wet it can potentially become a conductor. While the possibility of this happening is low is still something to be considered.

3. Wearing leather gloves is not a bad idea. I’ve gotten blisters while practicing.

The throw bag and line are an easy to carry, versatile means of launching and supporting your antennas. I’ve used it at Field Day to place antenna support lines over some lamp poles and on a Dxpedition to get the support lines over a tree. Of course I use it most of the time when I operate in the woods. The throw bag and two lengths of slick line are always in my “go bag”. I sure you too will find it a welcome and versatile addition. Have fun!
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John Kalotai, N1OLO, is an avid QRPer, PSK operator and outdoorsman living in Trumbull, CT. For additional information: