"between two trees"

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WA4RNT, Oct 14, 2009.

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  1. WA4RNT

    WA4RNT Ham Member QRZ Page

    Yeah ok...can't figure best way to put dipole between two trees...QTH in Louisiana and lots of wind especially during hurricane season...Tying direct puts to much tension on wire...and the only springs I find are the small 6" ones...these are 6" long & 1" dia....
    thought bout putting 6" springs at each end of but not sure if they are efficient enough...
    Suggestions welcome...
    Thanks 73s,
     
    Last edited: Oct 14, 2009
  2. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    A better way is to put a pulley at both ends (preferred but at one end may work) and then run ropes through the pulleys attached to weights near the ground and attached to the end insulators of the antenna. That way the antenna is going to be tight and the trees can move all over the place.

    Springs can be problematic especially if the wind is high and the tree is moving very much.

    Glen, K9STH
     
  3. K2XLG

    K2XLG Ham Member QRZ Page

    I agree...pulleys are your best bet. Try to use trees that don't sway around too much. Use heavier than normal wire...maybe 8 ga stranded or so. And set the amount of counterweight so that there's a little slack. Also have enough rope so that you can drop one or both ends in case you get some really nasty weather heading your way. Be sure to use a good grade of pulley...one with ball bearings. If you set this up carefully, it will survive for a while. Best drop it when hurricanes are on your doorstep though.
     
  4. K9ZMD

    K9ZMD Premium Subscriber QRZ Page

    Don't Over-Engineer the Project

    My antenna during many months of portable operation in Wisconsin was a doublet strung between two trees (one was a walnut tree, the other some kind of fir tree). I used one of those HyperDog sling shots to get a line up and over each tree. Once the lines were tied to the antenna end insulators, I drew each of them tight over the top branches of the trees and up came the antenna. I tied the far end of each line around the tree trunk. No fiddling around with springs, pulleys, or weights, and I didn't have to climb anything. I only used common #14 stranded electrical wire for that antenna, but it never broke in spite of mucho wind and impressive treetop sway.

    That installation was only temporary, intended to be easily put up and taken down because I only stayed there 3 - 8 weeks at a time. However, if I ever wanted to make it a permanent installation, I would only change to stranded copper-coated steel antenna wire and some heftier (and UV resistant) supporting line. 73

    Gary, K9ZMD/6
     
  5. M0DSZ

    M0DSZ Ham Member QRZ Page

    Using polyester rope at each end, my 200ft wire is equivalent to 14 to 16AWG stranded copper (flexible conduit cable) with a good PVC covering. Ends are reinforced with a loop of thin fencing wire through the insulators and this temporary arrangement has been up 5 years. The only damage was abrasion by the trees through the original polypropylene rope, this material being a little less resistant to sunlight as well, so I cut off a few branches.
     
  6. K2XLG

    K2XLG Ham Member QRZ Page

    Yeah but guys, we're talking about a location that regularly experiences hurricane winds of 100 to 150 mph. I have a friend that lives just west of New Orleans and he's told me that you just can't imagine what it's like when debris is traveling horizontally across your yard and the wind is trying to tear your roof off. With that in mind, the "extra heavy duty" approach would have to be the way to go.
     
  7. K5MDG

    K5MDG Ham Member QRZ Page

    I live in South Louisiana and plan to set up an antenna like this. I have a 40ft tower/mast in between 2 trees with enough room for an 80m dipole.

    Hurricanes don't just popup out of nowhere though. There's plenty of time to drop the wires and lower the mast...also to pack a bunch of stuff and get the hell out of Dodge!
     
  8. WA4RNT

    WA4RNT Ham Member QRZ Page

    Oookay guys...all great suggestions..and with much deliberation I've made my choice...
    I intend to use tuex pulleys at each end and use counter weights on the ends of the rope...
    Merci ...merci beau coup..tout est bon..
    73's:):):):):)
     
  9. KB4MB

    KB4MB Ham Member QRZ Page

    Of course the best solution is an antenna that you can bring down super quick. If there is a hurricane, bring it down. If not, put it up! Two trees in the clear with pulleys are the best if you can do that. Me, I have a house I contend with in the middle, so I am skunked.
     
  10. AD5ND

    AD5ND Ham Member QRZ Page

    I once saw a post that used door weights inside of PVC pipe filled with water to act as shock absorbers. This kept the wire antenna tight and kept it from jerking when the two trees swayed. My experiance is, any antenna that uses more than one tree is temporary.
     
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