need ideas to make my wire antenna more durable

[KJ4OLL]

Hi,
I would appreciate some advice/ideas on my wire antenna problems.
240ft long Doublet, center fed w/ 600 Ohm ladder line.
Works great when it is intact!
Rohn 25 tower for the first 40 ft., then a fiberglass mast for the next 40 ft.

One 120ft run is over a tree on the West end of the property.
The rope is over the tree, the wire is in free air.
The East run is the problem.
The furthest tree to the East is still too close, the wire is over the tree.
Wire breaks every few months. I don't know if Squirrels are chewing it or it is just the branches & wind breaking the wire.

I spliced the 14gauge stranded copper, but it broke again in the same place.
Will try a "Western Union" splice next, but are there better options?

What if I used some heavier 12 gauge stranded for the part that goes over the tree?

Does it make a big difference if one side of the doublet is the original 14 gauge 120ft, and the other side is 80ft of original 14 gauge, and spliced to 40 ft of 12 gauge?

Or what if I encase the 40ft over the tree in some plastic tubing, or heat-shrink Teflon - looking for a way to "armor" the tree contact part without inducing problems w/ the Physics.
73
Frank
KJ4OLL

[KA0HCP]

Bigger wire!

14AWG is marginal for a run of that length, and if you are going to have it rubbing against trees, the outcome is completely expected.

I would strongly recommend routing the wire through an insulator supported by the tree to eliminate contact and friction.

[W1ITT]

For wire, Davis RF makes their FlexWeave in both naked and coated versions.  You might try the coated stuff in #12 where it transits the tree branches.  You will hear people who don't like FlexWeave, but I have over 600 feet of it in open wire line in two separate tree supported 2-element 80M phased beams, plus almost 300 more feet in the arrays.  I've never had a failure in 7 years.
When I run across a tree, I do not used rope.  I use stranded aluminum or galvanized steel wire, sometimes coated but usually bare, whatever I can find at Home Desperate.  Every few months I go out and yank on the tie-off lines to move the wire where it goes through the tree, to prevent it from growing in.  A couple of mine have gotten ahead of me, but except for a failure where a 100 foot pine took a tumble in a hurricane, I've not had a failure in support lines in at least 10 years.  I use a pneumatic tennis ball launcher  to get things up closer to the ether.
FlexWeave is cool because you can tie it in any of the knots you learned in the Boy Scout Handbook.

[KA2DZT]

I just put one of my ropes through plastic tubing to prevent it from breaking in the trees.  I think it should hold up well.  I used about 15ft of tubing, part that runs over the tree.  I get my lines over 100ft trees with a 9ft fishing pole.  Rarely do I need to do two casts.

No problem with mixing 14ga and 12ga wire.

For my antennas I use 3 pair or 4 pair telephone wire.  I tie all the conductors together.  The stuff is surprisingly strong and never had any failures, except when a 100ft oak tree came down and broke the phone wire.  I use phone wire because I have 1000ft rolls of the stuff.  It is not used much anymore with everyone using cell phones.  Land line phones are fading away into history.

Fred

[WBear2GCR]

Ur ant ought not contact anything, a tree is not a good thing to touch. It will detune the ant and also may arc or otherwise shunt RF energy through it. If ur lucky enough to be at a null on the wire, both current and voltage (I guess, if they both ever happen) then I guess it will have minimal effect.

Afaik there is no "teflon" shrink tubing.

Anything you put on the wire will need to withstand UV. Most plastics do a rotten job in that respect. Also you have to take into account both wind load, water and ice load and weight.

I'd opt for the heaviest wire you can fly... also a bit depends on if the wire has any "give". If the end past the tree has solid guying, that may be source of your breakage. Perhaps you might consider using a spring or a weight to tension that end?

No problem making a splice and increasing the wire gauge.

Got a diagram and/or pix??

                    _-_-

Btw, where does one get a 40ft fiberglass mast and how does one lift it up and secure it to the top of Rohn 25? Curious about that.

EDIT: I re-read your post. How far is the troublesome tree?? How tall?

There is zero need for the end of the antenna to be horizontal. A short amount dropped down, or perhaps even guyed off at an angle will not materially effect the way the ant works. So, assuming that tree is just slightly short of the distance you need, then run a guy rope (probably with a sleeve where it goes over the tree) over the tree, add an insulator just past the branches and go to it with the rope and the ant. Let the ant hang down to the ground, or similarly guy it off at an angle to another tree with another rope. That's the general plan.

[K1JJ]

Hi Frank,

A few more tips:

Supporting a dipole in the middle, at the feedpoint, is probably the most important advice for antenna longevity.

If trees are used for end supports, the dipole legs need to be very loose and sloppy to handle the extreme winds and occasional ice loads. Some use pulleys and weights, but I find them not needed IF the center is supported and the legs are slack.

For tree crotches, I always use stranded steel EHS 3/16" guy cable.  It will never break and slides thru the tree easily.  If it gets stuck after years of use, just tie it to a car or truck and pull it out.

#10 wire is probably what you need for the dipole legs.  The Home depot black 500' insulated stranded spools work FB. Copperweld is even stronger, but a handful to work with. Wear eye protection.  Be sure the copperweld does not rub an insulator hole in the wind or eventually the copper coating will rub off and the inside steel will rust and break.  I usually tape each insulator hole and wire together to immobilize movement.

Feedline to dipole legs junction:  Mechanically secure everything well and use jumpers soldered to connect.  You want wind to have no effect on connections.  Movement is an enemy to eventually work harden and break wire connections.  Most antennas fail at the splices. (At feedline connections, wire connections and insulators.)

If the copper wire is bare, it will last MUCH longer if solid rather than stranded. The smaller the strand diameter, the easier it is for the weather to eat it up.   The insulated Home Depot wire, if sealed at the ends, will keep the stranded wire shiny for many years.  The PVC insulation will add capacitance and make the antenna seem a few feet longer, but will have no meaningful effect on radiation.

Tom, K1JJ

[Jim, W5JO]

If you must run the wire over tree limbs then use garden hose for tubing over the limbs to insulate the wire from the limb.  Fix the hose so it will not move down the wire.  A 25' garden hose is relatively cheap and should stand sunlight for years.

I have some garden hose that is approaching 20 years old.

[WZ5Q]

Howdy Y'all,

I have always had good luck with the "Brute Force" philosophy, in my experience bigger is usually better.  

I use 10 gauge wire at a minimum for my antennas. If the antenna will be in the clear and not touching anything, I prefer to use the 8 to 10 awg copperweld, otherwise I will use the insulated 8 to 10 awg stranded.

Using this size wire, HUGE insulators, as well as 3/8" to 7/16" black marine 3-strand nylon rope over the tree tops and branches has performed well for me over the years. Antennas have stayed up for 5 to 8 years without incident.

I had a 1058' Loop up at a 100' height using 10 awg copperweld, fed with 600 ohm OWL feeder. I had this antenna oriented in more or less a circle thanks to several very high pine trees in terrific locations. This antenna stayed up for 8 years until I took it down about 7 years ago. I am still using some that same rope for my present antenna, a  160m Doublet.

I said previously "without incident", well there was one...
The tree (especially Pines) will grow around the rope if you don't go and move it every now and then. I had to tie the ropes to the truck to get most of them loose. The ones that didn't come loose and snapped at the tree top, I had to shoot the insulator with the 7mm Mag to drop the wire.  

Take Care,

[KB2WIG]

Here's watt  I did...    For my 80m dipole, I ran 14 AWG THHN between two trees. This is the 'plastic' coated stuff, available from places like the Homely Despot. It is suported at the center by a nice tree. There is a suport rope holding the center insulator and the coax. Nested in the crotch of the tree I placed a few feet of garden hose. The suport rope goes through the hose, allowing me to raise/lower the feedline. Let the tree grow, I dont care. The ends of the dipole have insulators tied off to ropes in trees.. There is enough slack  -  so far, the ants haven't fallen much. ( I made the 80m into a fan dipole and ran a 40m dipole off of the center, sorta like a "X".  One of the ends fell down, so now its something like an inverted U.)

How did I get all this up you might ask? I had the use of a compound bow from a local benevolent OM.  I only limped a bit, as no bones were broken, and the boots were old. Use practice arrow heads. To get the hose up, I ran the support rope through the hose, and ran another rope through the hose, threading it back through the hose again. This contraption is hoisted up to the crotch of the tree. By pulling the 'threaded' rope back and forth, holding both ends of the rope, the hose is centered into the crotch of the tree. The support rope can move back and forth, unvexed. If you want to leave everythig up, just tie things off. Or let go of one end of the hose rope, and gentely pull the other.

Next time, I'll use the EHS cable.

Oh yeah, 'split bolts' are nice to use. They are Cu, you don't have to solder them. Coat the splice with the plastic 'lectrical tape stuff. Its the right thing to do.

klc

Got my Festivus pole out today.

http://www.amwindow.org/misc/av/TomVuXmasSong.mp3

[W2PFY]

I used number 10 stranded covered copper wire. Before I put it up I hooked it up to the trailer hitch on my truck and stretched it till it broke. I then spliced it back together. It was hard to remove the insulation because pulling it that much embedded the insulation into the wire. I did this with the thought that it would not stretch unevenly and upset the balance of the antenna. Its now up about 100 feet between two very tall pine trees going on 12 years!  I thought that the negative consequence would be that the wire would be weaker but it has proved otherwise... It is cut for 1.885 mhz.

[K3ZS]

I now use copper clad steel (Copperweld) wire for the antenna, 3/8 inch double sheathed dacron rope and a pulley and weight at one end.   Antenna has been up 15 years, but the tree is about to expire.  I tried flexweave once, it is OK for short term use, but it frayed where there were stress points and was replaced.

[flintstone mop]

thanks Tom
The reply eased my mind about not having to get anal with the ends of a long dipole needing the pulley and bucket.
I have a 240 foot dipole fed by OWL and the center is not supported. There have been two failures. I lost the end in the tree from rope-to-antenna wire failure and the second one was antenna wire failure at the feedpoint. The stranded wire is very nice to work with, but gets fragile in violent winds. Probably #12 or14g.
#10 stranded from Home Despot will be the rebuild in Summer.
Fred

[KB5MD]

I use stainless steel welding wire for all my wire antennas, about 18 gauge.  The only thing is you will have to use split bolt or something similar to connect feed line
to the antenna.  I took a 160 meter dipole down yesterday that had been up 4 years with no breakage.
After clamping the feed line to the antenna, I always coat the connection with the liquid tape available at the big box store.

[N2DTS]

240 feet with OWL hanging from the center?
No wonder it breaks!

The stainless welding stuff sounds great.

I got some wire from 'the wireman' that was very nice and cheap.

https://www.thewireman.com/

For short ones I use 12 solid copper.

I might pull one of mine down and put this up:

http://www.ni4l.com/4-band-80-40-20-10-meters-multiband-fan-dipole-antenna-flex-weave/

My fan dipoles were always wacky tuning and tangled messes.

[W9ZSL]

I'm using #14 (or maybe 12) copper weld for a 75 meter dipole with a center support and balun feed.  It's up 20 feet on both ends and middle.  

This fall a tree came down on it just left of center.  It bent the front mast and center support.  I had a 40 meter hanging under it...soft-drawn insulated house wire.  I dropped the works and removed the 40 because I don't work 40 and the insulation was peeling.  I dropped the front-yard mast and straightened it.  I had an extra 10 foot piece for the center.  The other 10 footer had a slight bend so I cut off that part and replaced it with a 4 foot mast on the bottom.

I expected the worst for the center feed but to my surprise, there was no damage at all and the copper weld actually saved my roof from damage!  When the front and center masts bent, they absorbed the shock.

Everything is back in place, and since there is no additional sag from the 40 meter, the 75 is nice and tight...until the next tree falls that is!

On the plus side, that is one less tree that has to be cleared.  Come summer I'll get rid of anything else hanging over the roof and add another 10 Feet to the center for an inverted "V" 30' in the middle and 20' on each end.  I'll add a couple of traps and may replace the balun.

The copper weld is a beach to work with but snapping it is almost impossible.

[KJ4OLL]

Thanks for all the great ideas & comments!
On my way to Skycraft Surplus tomorrow to get some #10 AGW copper wire.

I use an "Air Boss" pneumatic launcher, with adequate pressure this thing will put the 1oz. lead weight in orbit!

Here is the way it is constructed. Wire is the white trace, white/black is the guy rope.




There are photos on qrz.com of the way the tower is done, and the maintenance procedure we are doing over the last two weeks of this month.

How about if I do not run the wire over the tree on the East end, just run a rope over the tree, and let the last 10-20 ft. of the wire hang straight down?
73
Frank
KJ4OLL

[KL7OF]

Lots of good ideas here....I like to hear first hand reports like these about what has worked and what has not worked....I agree with several ideas posted here....These have worked well for me putting antennas in trees...  (1)   It is hard to beat copperweld wire...Hard to work with, but worth the effort.   (2) a center support will keep your antenna in the air longer.  Split bolts or "kearney clamps" are excellent for antenna work.   Big wire and big insulators are the way to go...bigger is better......I question the use of stainless welding wire......Stainless does not conduct like copper....I have had a couple antennas made from stainless...one of 1/8 inch 7 x 49 stainless aircraft cable...It never did perform as well as an identical wire of copperweld...The other was of stainless welding wire .040 diameter....It worked but one that I made out of 14 ga THHN copper seemed to work better.....YMMV....Good Luck....Steve

[W9ZSL]

My dipole is cut for 3885.  I still have to get back on the air because I'm re-doing the shack.  When the antenna still had the 40 slung under the copper weld (which might actually be #12) , I was getting an almost perfect 1:1 SWR on both bands.  Surprised the crap out of me. The ground is excellent because I'm only a few feet away from the main water valve in the basement so I clamped on just below that.  Copper pipe not only feeds the water to the entire house but I have all copper pipes feeding hydronic heating.

[N4zed]

One thing I started doing is to have two pulleys at each support. One attached to the support line over the tree and one attached to a line through the first pulley. I also have a tether line attached to each of the pulleys.That way if the antenna wire breaks I can pull the second pulley back down and just re-thread the antenna without the need to re-shoot the tree. I have a 400' loop about 90' in the popular trees. I used to have 16awg stranded. I finally switched to 12 awg...boy that 12 awg is a lot heaver than the 14 !!!  The 14 awg broke last year and I just stripped the insulation back tied a knot behind the strip, soldered the wires back together sprayed some undercoating on it and pulled it back up...took all of 15 min.

Works for me....

Ken
N4zed

[WBear2GCR]

Frank,

I think you can let the last 10-20ft hang down, no problem. You'll need to adjust the tuning a bit, if this is a resonant antenna. I adjust mine by making the ant too long and looping the end back up the hanging bit to shorten it. No cutting required. Does not need to be an electrical connection either (for the looped up end).

The other option is pick up the end that would then be hanging with another rope/guy/insulator arrangement and go off at an angle away from the tree, but more up in the air...

Looking at the overhead picture, why not run the "east" leg rotated counter clockwise
(from the point of the image) to about the 2 or 3 o'clock position? It makes the ant a V, but it probably will have little effect on the radiation pattern.

[N2DTS]

Does the wire used really make a difference?
Say aluminum, steel, copper, silver plated copper, etc?

I know that thicker wire or a cage is more broad banded, but I thought if it was conductive you were good to go for the most part.

[K1JJ]

Does the wire used really make a difference?
Say aluminum, steel, copper, silver plated copper, etc?

I know that thicker wire or a cage is more broad banded, but I thought if it was conductive you were good to go for the most part.

Once you break out of the silver, copper and aluminum world, conductivity starts dropping off fast.

For example, steel, especially stainless steel, is about 40-50 times LESS conductive than copper.  I can see this having a meaningful loss effect on an OWL fed multi-band antenna where high current points are numerous throughout the legs at most frequencies. (especially the higher bands)

Much depends on the impedance of the antenna, current peaks and diameter of the material and frequency (skin effect) -   but in general, stick with the big three and we are FB.


Check it out. Notice the %ICAS column uses pure copper as the 100% reference standard:

http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/

I find this one interesting:

"16.60   1     Tin, Silver Solder"    (Tin / silver solder is 6 times less conductive than pure copper)

T

[N2DTS]

Ok, I will go with low oxygen gold antenna wire to get my well defined highs and solid and robust lows back.

I never thought much about the current points, guess that is why my rg214 has silver plating....

[KJ4OLL]

Hi,
I have a dumb question, not being an antenna expert yet. (could be 'nother few days before I know it all)
Bought this 240ft Doublet from Trueladderline.
Can't ask the vendor any more, as Charlie, K5JYB is SK.

If I replace the existing 14 AGW stranded w/ 10 AWG, not exactly sure how to measure the length, with respect to resonance.
LMR-600 runs from the shack to the Balun Designs Dual Core 4:1 Current Balun

The ladder line runs up about 60-80 ft to the center feed point "T", where one lead goes West and one goes East.

Should I measure from the end of the wire to the feed point to get the approximately 125ft. length for each leg?

WB2GCR  - I might just try changing the angle of the East side, just not sure what it would do to the pattern.

73
Frank
KJ4OLL

[KA2DZT]

Somewhat thicker wire of the same exact length will resonant slightly lower in frequency.  Thick elements are electrically longer to the RF than a thinner element of the same exact length.

It will take a little time to become an antenna expert.  I strung up my first wire antenna some 61 years ago and I still don't know much

Fred