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how to hang a dipole

Discussion in 'General Technical Questions and Answers' started by K7MHI, Jul 30, 2009.

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  1. K7MHI

    K7MHI XML Subscriber QRZ Page

    so I am having trouble figuring the best way to deal with getting a dipole up in some trees I currently have some trees in my back yard that are about80-100 ft tall. The Trees are on either corner of my back yard and I can string a 80m Grv5 or Off center fed dipole My house is about 14ft from one tree.

    The problem is how do I deal with the ladder line/feed line?

    My current install plan is to rent a genie hoist because I also need to trim up and fell a tree as well as some other high up work, so while I have this unit I will also put some big 2" eye hooks in the tree as high as I can get on the lift. I will then string up the dipole and put the line to the ground, this way I can weight the line and it can move in the eyehook for wind/tree movement with out ripping my antenna, as well as give the ability to repair antenna if needed by dropping the line.

    but the issue I am not sure about is if I have a end supported dipole 100ft in the air, with a ladder line dangling from the middle of it (the black dot) then cross over to the trunk of the tree with the coax feed will this stress the antenna too much?

    how do you deal with this or how would you suggest to put up an antenna in this situation?

    I should also add that right in the middle of the two trees almost equaldistant I have another tree about 50ft High that I currently plan to fell (unless its a awesome antenna rig tree) I didnt put this tree in the graphic


    if the image wont show up...
    Last edited: Jul 30, 2009
  2. W9GB

    W9GB Ham Member QRZ Page

    Why not a pulley on that eye hook?
    Then just like a sail boat ... you can change "sails" (your antenna).

  3. KA4DPO

    KA4DPO Premium Subscriber QRZ Page

    There's an old saying about antennas that say's " If you put it up and it stays up it wasn't high enough, if you put it up and it comes down it wasn't strong enough".

    I would also go with the pulley and eye hook, makes replacing them a lot easier.
  4. KD0HFZ

    KD0HFZ Ham Member QRZ Page

    Yes, a pulley is a great idea. Put some weights on the end, and then when the trees sway, the dipole wont be snapped, and you can change antennas faster.
  5. AG3Y

    AG3Y Ham Member QRZ Page

    The pulley is almost a necessity. You would be surprised at how much friction can be generated by putting a rope directly through an eye-bolt!

    The ladder line, or some open wire feed line, should not stress your center insulator much at all. Either type of feed can be much lighter than coax cable, and if you intend to use the antenna on many different bands, your losses will be much less.

    I would bring the ladder line as close to the house as possible, and only use coax to go through the walls of the structure in order to minimize losses as much as possible. You can use a 1:1 current balun on the coax line to keep RF out of the shack although I have had success in just making a connection directly from coax to the ladder line ( ! ! ! ) and not experienced any RF problems. I know, maybe I am just lucky !

    Good luck, and let us know how things come out !

    73, Jim
  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    Hi Kelly,

    There are many ways to get an antenna into a tree. The bucket lift is but one. Use whatever works for you but I'd advise you to have someone on the ground to help (or call 911 if needed).

    Screwing anything into the tree is bad for the tree, could pull out, and is also a poor subsitute for a pulley. Better to loop a rope loosely around the tree, above a branch(es). A section of rubber hose will lessen the tendency of the rope to become embedded into the tree. Use rope that is UV-resistant. If you tie this rope to a pulley, you can then use the pulley to raise/lower the antenna. I use a nylon & stainless hardware closed pulley. Instead of tying the antenna rope off, use a counterweight near the bottom of the tree to maintain tension on the antenna wire. I used 5- and 10-lb dumbell weights. McMaster-Carr has a chart regarding the characteristics of various fibrous rope: ( I use ΒΌ" double-braided nylon rope.

    There are some choices for antenna wire. Some like solid copper-coated steel, aka CopperWeld(TM). Others prefer hard-drawn stranded copper wire. I use 12ga 259 strand "Flexweave" wire from Davis RF ( for long single-wire antennas. My 4-wire 80m cage inverted vee uses 14ga Flexweave. They also have a fine selection of insulators & feedlines. My antennas are all coax-fed, so I can't make suggestions regarding ladder line.

    Bryan WA7PRC
  7. W9GB

    W9GB Ham Member QRZ Page

    You can also use the counterweights (cast or pot metal) from old sash windows!
    I took 4 window weights from my parent's old house (free) -- when they were replacing windows several years ago. I cleaned and primed them to prevent further oxidation -- and they are in my "antennas to go" box!

  8. K7MHI

    K7MHI XML Subscriber QRZ Page

    thanks for the tips, yes I like the idea of a strap around the tree I might ponder that a bit.

    Its good to have the advice on the ladder line and stress that was my primary concern with this setup I didnt want the weight bogging down the antenna so much it causes problems. I will likely run the ladder as close to the house.

    Thanks for the advice guys!
  9. WA1ZPD

    WA1ZPD Guest

    Hmmmm, those are some awful skinny trees you have there. LOL :D

    Good luck with the antennas
  10. W4HAY

    W4HAY Ham Member QRZ Page

    I've been using large eyebolts into trees for over 50 years with good results. Last time I visited my hometown, a tree in which I installed one in '53 was still very healthy.

    The tree will eventually grow around the eyebolt, so you'll have to back it out occasionally if you don't leave enough of the shank exposed.

    I run and endless loop of line from the eyebolt/pully down to two large hooks about head-high which I use to secure the loop. The ends of the line are tied together with bowline knots, and the antenna secured at the same point. Either leave enough slack, or use counter weights, to prevent tree movement from parting the antenna.

    Cement in an old paint can with an eyebolt down the center makes a cheap counter weight.
  11. WA7PRC

    WA7PRC Ham Member QRZ Page

    Certainly - necessity is the mother of invention (not to be confused with The Mothers Of Invention)! :D

    I should've mentioned that I had to support the center of my 4-wire 80m cage inverted vee (480' of wire + ferrite choke 'balun' + LMR400 feedline) and one end of my 40m dipole. I needed a lot of counterweight. Shorter/lighter antennas will need less counterweight.

    My counterweight can be easily adjusted by adding/removing weights, if/when I make changes to what is attached to the other end of the line. I first tried a plastic 5 gallon bucket filled w/ rocks. I fitted a piece of plywood into the bottom of the pail to prevent the rocks from pushing thru the bottom. It worked OK but I was concerned that the wire bail might've pulled out.

    Bryan WA7PRC
    Last edited: Jul 30, 2009
  12. AG3Y

    AG3Y Ham Member QRZ Page

    If you do use a bucket filled with loose material ( rocks, sand, etc. ) be sure to punch some drain holes in the bottom of the bucket so that any water that collects in the bucket has a chance to drain out. Otherwise, you will find that the bucket will become much heavier, and put undue strain on the antenna wires! Filling a bucket with concrete may be a bit of overkill, but I like Greg's idea of the sash weights !

    Make sure you teather the bucket or counterweights near the bottom, so they don't swing around with the tree motion. Remember the bridge "Galloping Gerty".

    73, Jim
  13. K9PAC

    K9PAC Premium Subscriber QRZ Page

    Great idea running an endless loop thru each pulley. You can then tie a round ring or pear ring to each endless loop for the antenna. Or tie multiple rings to the endless to run several wires parallel to each other for mono band or fan dipole.
  14. K7MHI

    K7MHI XML Subscriber QRZ Page

    so this endless loop idea, to get this picture ini my head you created like a stage curtain-pull with a pully at the top and bottom and raise and lower your dipole like a big flag or curtain?

    this thread is fun, I am getting a lot of ideas specially the part about multiple arrays on the same line, this pully rig as mentioned in the last post would allow different antennas up in the sky
  15. W1GUH

    W1GUH Ham Member QRZ Page

    There's an easy, cheap, and very effective alternative to the complicated pulley/weight "moving tree" solution -- screen door springs.

    You only need one (they're very cheap) in one of the support ropes for the dipole, are all you need to protect your wire antenna from swaying trees, and they last a long, long time. I've had them up for > 10 years and they were still going strong. And, if you ever need to replace it, they're and very easy to replace.

    Advantages over the pully/weight solution.

    1) Much cheaper and easier to install. I'd guess that just one pulley alone will cost more than a screen door spring. 'nuff said.

    2) Potentially safer. A proper pully/weight situation needs fail-safe protection for broken wires, rope, etc. A spring needs none of that.

    3) Looks better. The spring itself is 'way up there...hardly noticable at all, while the pulley/rope/safetyline of a pulley/weight lashup has multiple ropes, a pulley, a weight, etc. With a spring, all's you've got coming down the tree is the support line.

    I know of no advantages the pulley/weight solution offers, I've never heard of any. What I know is that all of us using springs have been doing so since I'm a ham (1960) and I've heard of no problems with them. About the only potential problem is if the spring rusts and breaks...but so what? they're easy and cheap to replace. Alternately, it's very easy to periodically inspect them for soundness.

    And they're perfectly effective -- I've never had a dipole, or a folded dipole of 300 ohm twin-lead break. NEVER.

    The other comment is why a G5RV and not a regular dipole, fed with either coax or balanced line? I'd think that a regular dipole that's as long as you can get it fed with balanced line and tuned with a balanced tuner would be more versatile than the G5RV and offer easier construction and installation. But then, being a straight dipole type, I don't know that much about G5RV's.

    Whatever you do...ENJOY! Wire antennas as a ball to play with.
  16. WA7PRC

    WA7PRC Ham Member QRZ Page

    A good idea, except that sand will tend to fall thru the holes, making your counterweight lighter over time. :(

    Another good idea! However, I haven't noticed that w/ my setup (the counterweight hangs just above ground). Snow loading is my only issue (the counterweight gets lifted several feet). A few sharp pulls on the rope fixes it 'til the next snow.

    Galloping Gertie = the first Tacoma Narrows Bridge :eek:... just down the road from me. I've driven over it many times, and flown over it once.

    Yes. You'll need to have no tree branches in the way to raise/lower the antenna(s).

    I paid $10 at the local industrial supply emporium for a nice 3" diameter nylon/stainless pulley block. A pulley or spring has to be put up into the tree. Neither has an advantage.

    A support of any kind needs fail-safe protection for broken wires. This includes springs.

    My support uses one rope that runs parallel to the tree (a 75' tall Cedar). Only the bottom 15' of rope can be seen. If I move the counterweight up, it can't be seen at all.

    It's super easy to raise/lower the antenna(s) using a pulley/rope. Just use enough rope to facilitate this. Coil up the excess when the antenna is in its operating position.

    Yes, periodically climb the tree to inspect/replace the spring. Periodically inspecting/replacing rope can be done from the ground. If a high-quality pulley is used, the tree needs to be climbed only on initial installation.

    Agreed! :) If I could have only one antenna to cover multiple bands, I'd go with a doublet/ladderline/tuner. Suggested reading:

    vy 73 es gud dx,
    Bryan WA7PRC
  17. W4HAY

    W4HAY Ham Member QRZ Page

    I use a pully at the top only. At the bottom, I use two hooks about 18-24 inches apart, the lower one facing down and the upper one facing upward. I wrap the line back and forth between them, then tie it off. When properly installed, there will be 10 or so feet of bight for wrapping. If a counter weight is used, the line that it's fastened to will be routed through two hooks placed one above the other as close together as possible, the open ends facing each other. This keeps it from swinging in the breeze.
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