slinging a line over a tree

[N0BST]

I tried to set up a "field day"-style ham radio antenna without success.  I didn't want to spend the big bucks for the slingshot/reel combo advertised on QRZ and in the ham magazines so I bought my own slingshot (Daisy P-51 which I understand is pretty good and looks very similar to the firing end of the one in the ham ads) and an old fishing reel I bought at a garage sale.  I tried firing a weight over a tall pine tree, but the best I was able to do was about 90% of the tree height.  I'd have been happy at that point but it didn't go clear through but got tangled in the high branches.    I was using nearly a pound of weight (a short bolt and nut from some surplus satellite hardware I had) as anything less didn't pull the line well enough.

Since this sling/reel combo wasn't an all-in-one device I had my daughter point the reel at the top of the tree while I fired the weight.  I've heard of hams being able to do this with no more than a 3/8" socket wrench piece but that wouldn't have been nearly enough to pull the line on my reel.  

I said all that to ask this- is there a way of determining the optimal size counter weight and fishing line?  I'm sure it's probably been done; I just need to learn what it is!  Or maybe I just need a better reel?

Thanks,

Scott Todd

[K6JEK]

This is a great physics problem but we don't have the equation for the slingshot and I've forgotten the math. I will say, though, that the EZ hang comes with much smaller weights than you're using, 1 oz

[WZ5Q]

Howdy Y'all,
I have built my own slingshot/reel combination as well.
It is a Cobra wrist rocket purchased from Academy with a Zebco 404 reel mounted onto the "Sight" bar.
I use 12lb Test abrasion resistant mono-filament line (Silverthread) and a 4oz lead fishing weight.
This combination will propel the lead weight over +100' pine trees with no problem.
You have to pull the rubber bands back a LOOOONG way though!!  
Yes, when the bands break, it is painful...  
When the bands get cut up, I will shorten them and it seems to propel the lead weight with more control, albeit with less range.

Here are a few pictures of it.

Take Care,

[W1RKW]

I've never tried the fishing reel method as a de-spooling device.  I've always laid my line out on the ground in a tight zig-zag pattern and just fired away. I don't use mono-filament but rather thin nylon string one can find at the hardware store.  I find mono-fil fishing line prone to tangle easier because of the twist from being stored on the reel.  Braided fishing line I have not tried but do know from fishing it is prone to wind knots due its high strength to size ratio and doesn't have memory like mono. Braided fishing line has it benefits and faults but may not be good especially if it gets tangled in a tree. 

As far as the projectile goes I would think heavy "bean bag" type projectile would be best.  I've always used a lead sinker but they like any other solid object will be hard and bounce off of branches and tree trunks. I have yet to try this but me thinks a bean bag made of lead shot or BB's, maybe 1.0 to 1.5 inches in diameter, would tend to not bounce and would just drop upon impact.

[KC2FXE]

This Is what i like to use to shot lines over the tree s
                                kc2fxe John

[N0BST]

I'd love to see the construction details on that one, John!  What do you use for a weight and how much pressure do you use?

Scott

[VE3LYX]

Been there. Got frustrated as well. HOWEVER! I junked the slingshot and put the reel back on the fishing rod. Tied a half roll of electrical tape to the line and aimed for the top of the tree about 50 feet up. One shot was all it took. Cleared it easily. Tied a string to the line and pulled the string up by pulling on the fishing line. Then tried the nylon rope from the antenna to the string and was in business quickly. Thought it might have been a fluke but strung up another antenna in preparation for winters activity a week ago Monday. I need not have worried. Same deal only this tree was higher. One shot , Right where I wanted it.  My advice is give the slingshot to a Slopbucket ham. Then do some reel casting. Piece of cake.
Don

[KC2FXE]

 reply to Scott
      The weighted tenis ball 4.5 oz of shot in side to ball and run about 75 to 80 psi to launch the ball  over the tree.
 John

[K6IC]

Scott,

Have used an arborist's line slinger -- the Big Shot -- for many years.

This,  plus Mason's line (thin three-twist Nylon line)  laid out on the ground in zig-zag pattern  and an 8-10 ounce Shot Bag easily allows placement of lines in trees.   We do not have tall,  tall trees,  which might dictate somewhat lighter shot bags.

The Masons line is very slick,   and dead limp.   The bag is heavy enough to ensure the line does not get hung up in the tree (which is good,  as the shot bag is ten or so bucks).

This reliable solution is not the cheapest around,  but works well,  and can be shared among a group.

FWIW here is one supplier of the Big Shot:
http://www.sherrilltree.com/Big-Shot-Classic-Kit-with-2-Four-Poles

Shot Bags:
http://www.sherrilltree.com/Professional-Gear/Throw-Weights_2/Neo-Throw-Weights

It is quite possible that lower prices can be found on the net,  as believe that Sherrill is the manufacturer of the BS,  and may feel the need to "protect" resellers  by selling at full retail (a guess) .

The Mason's line can be found at the Orange colored Big Box store.

FWIW,  GL    Vic

[N4zed]

What I use--->





 

Ken

[Steve - K4HX]

Always best to have two balls.

[Ralph W3GL]

Always best to have two balls.

Yeah, but you can still get the job done with one if you
try hard enough...

[K1JJ]

Next April Fool's Day:   Shoot your boss in the BA's with that golf ball arrow...    

T

[Edward Cain]

Ok guys, now that we have the ends of the antenna in the trees, what do you use to accommodate the stretch and droop do to wind? I have contemplated pulleys and bungee cords.

Ed/KJ4JST

[WZ5Q]

Ok guys, now that we have the ends of the antenna in the trees, what do you use to accommodate the stretch and droop do to wind? I have contemplated pulleys and bungee cords.

Ed/KJ4JST

Howdy Ed,

I use 3/8" Black Treated Rope like whats used for shrimping nets, and just tie it to the insulator on the end of the 10AWG Ariel wire. The rope then goes over the top of the +100' Pine tree branches and back down to the base of the tree where it's tied off.

No Pulleys, No Bungee chords, just enough slack in the rope to let the +100' trees bounce & swing around in the wind. The 10AWG Ariel Wire usually survives longer then the rope. The last 160m doublet I put up has been in the air for the last 6 years with no incidents or breakage. I had a 1058' Loop up at 100' for about 7 years before I sold that property.

One note...
You must remember to go out and move the ropes now and again to keep the tree from growing around it. That makes for an interesting problem. Can anyone say 7MM Mag?? 
 
Take Care,

[VE3LYX]

Actually I do all my tree trimming here with a Winchester 1200 Pump 12ga and #6 shot
Don

[K4RT]

Ok guys, now that we have the ends of the antenna in the trees, what do you use to accommodate the stretch and droop do to wind? I have contemplated pulleys and bungee cords.

Ed/KJ4JST

I use a pulley with my inverted-L. Photo attached.  The pulley is secured to the limb with an eye-screw and small grapple hook, and the Dacron cord is tied off to a screw-eye in the trunk about 6 feet above the ground. I climbed up there (about 45 ft.) Sunday and the pulley and hardware are in excellent shape after two years.

[Steve - K4HX]

Use marine grade pulleys and you'll never need to worry about weather/aging problems.

[W2PFY]

Always best to have two balls.

Would one ball lead to a premature launch?

[John Holotko]

Back in the 1980's I used to use fishing line and a bow and arrow to shoot a line into the trees. I has no problem getting a line over the tallest of trees and getting it down the other side so I could pull a rope.  That's how I managed to pull up an balanced line fed 80 meter Inverted Vee which served me for well over a decade. Only periodically did I have to lower it to work on the feed point., then pull it back up and it was good to go. It survived all sorts of storms, winds, and weather. The antenna put out a great sig on 75, 40, 20 and 10. I used it for virtually all my transmitting and receiving needs. 2 or 3 years ago it was finally destroyed in a massive nor'easter that came through toppling trees, downing wires, etc. One leg of the antenna was ripped off and the feed line was pulled loose of the building, blown skyward and now still sits tangled in the top of one of my tallest trees. To make matters worst when I tried to lower the good half to fix it I discovered that the tree had grown around the ropes and I can no longer pull it. Unless someone physically climbs the tree and cuts it free its up there for good, but useless. So theoonly alternative is going to be to fire up new line, pull new rope and hoist a new antenna. I have the insulators, wires, feed line etc ready to go. Since my bow is missing a string I am going to try to use a slingshot this time. Thanks to the advice and comments here it may help guide me through the process. I am going to wait till the leaves are down in the fall so I can get a cleaner shot and less chance of tangles. As long as I can get it over one or two of the higher branches I should be good. If the slingshot fails then I'll try to go back to the bow and arrow.  The neighborhood has changed and I would prefer to use the slingshot as it is less conspicuous.  Some of the new yuppies living around here might have a heart attack if they see me outside with a bow and arrow in my hand.  . So I'll do the slingshot first and if that fails I'll have to go to the ol' trusty bow.

[KB2WIG]

" Since my bow is missing a string '

J,

Get yerself some weed eater line, string up yer bow, and yell Die yuppie skum!! Let yer fish line fly.

Its the right thing to do.


klc

[K1JJ]

The problem with ropes getting over-grown and stuck is a common problem.

I solved it by using steel guy cable.  If cable gets stuck, just hook it to the truck and give it a pull. Works every time to free it up for a few more years.   Plus, wire cable never breaks from branch friction,  like ropes do in the wind.

I find the best stuff is standard 1/4" EHS guy cable. It is very smooth.    In contrast, the fine stranded aircraft cable is very coarse and has a tendency to saw its way into the limb quickly.

Two more tips:

1) Support the dipole in the center if possible for less stress on the ends.  Tree supported rope ends with no center support don't last very long unless steel cable is used.

2) Pull the rope or cable down to the ground hugging the trunk of the same support tree.  Tie it off on the tree trunk near the ground. If the rope uses the tree for support all the way down, there is little sawing movement at the branch.  However, if the rope pulls down at a 45 degree angle and does not follow the tree trunk, (anchored farther out) whenever the tree moves in the wind, the rope will cut its way into the branch - or quickly tear itself apart at the branch.

T

[KB2WIG]

"The problem with ropes getting over-grown and stuck is a common problem."

You can run your suport rope/cable through some old plastic tube or garden hose. Its just a bit tricky getting the tube into a limb crotch.  Use a double length of fishing line to hold onto the tubing. You pass the suport rope and the double length fish line/tube up and over yer tree limb. if the tube jams so it wont ride over the limb, use the fish line and give it a real good jerk. After a few tries, you'll get the tube up where you want it. Then let go of yer fish line and pull it down. Its reel easy to do. Right.

The tension of the support rope will keep the tubing in place. I have the pulley attached to the above set up and raise or lower the feed line and center insulator. If only I had it up higher in the tree.

klc

[K1JJ]

Yep, sounds like a plan.

Another way is to attach the end of a steel EHS guy cable to a pulley.  The steel cable goes thru the tree limb. The pulley gets pulled up and hangs out a few feet from the tree limb top and gets a rope thru it which supports the dipole.

This is how I do my trees now.  We lose a few feet of height, but the pulley always works smoothly to drop the dipole. The pulley can be pulled down for servicing if needed.  A weight can also be attached to the end of the rope to let the dipole move in the wind.

T

[John Holotko]

" Since my bow is missing a string '

J,

Get yerself some weed eater line, string up yer bow, and yell Die yuppie skum!! Let yer fish line fly.

Its the right thing to do.


klc

I fully agree.  And rest assured if the slingshot doesn't give me the desired result I will definitely use the bow and arrow. Yuppies or no yuppies that antenna is going up.