Q: ROPE FER WIRE ANTENNAS

[ve6pg]

...hi from tim...i have alot of trees, very tall, and i am using some fer supports of wires... i'm planning on putting up a 2-wavelength loop, open wire fed, fer 160.  ok, what are ur suggestions for long lasting, and strong rope. uv is important of course. i've used that yellow-poly stuff fer yrs, knowing it will have to replaced..gud stuff, cheap and strong. i'm sure the black dacron will be mentioned, but what have u used, and received gud service from?...sk...

[WBear2GCR]

One word:

Dacron

Think it is polyester actually.

NOT polypropylene!
Nylon not awful, but not that good.

                _-_-WBear2GCR

[John K5PRO]

The black dacron is excellent in UV.  I installed my trap dipole with long stretches of it at the ends, 10 years ago, in the New Mexico sunlight, and it hasn't quit yet. I think the broadcasters use Phillystran, for guys. 

http://www.phillystran.com/

[Jim, W5JO]

Polyester.  Cheaper than the black dacron and thus far it has served as well as the dacron.  It holds up my 44 ft. vertical very well, even in wind gusts up to 65 mph.

[W4EWH]

The "Yellow Stuff" doesn't wear very well when rubbed: my dipole just came down after less than a year. The tree's motion had rubbed through the poly.

I know the Antenna Book says to use a pulley and a counterweight, but that assumes that you can climb to the top of the tree to install one ...

73, Bill

[ve6pg]

...what abt that white stuff, used in marine use?..sailboats, etc?....sk..

[WU2D]

I have woods out back but the trees are not hardwoods and it is dense.

I have big 75 - 100 ft high pine trees that do a lot of swaying and I generally use the conventional "over the treetop" method. I usually have a bungee on the ground end for sway and shock damping. This setup lasts around two years before I have to change the ropes. The failure is either rope rubbing or tree branches coming down on the wire during storms!

The longest lasting setup was when I shot a pulley rope over the far tree and suspended the pulley with steel cable. The poly rope was threaded through the pulley and a counterwieght was put on the bottom. This setup lasted 5 years.

Mike WU2D

[n2bc]

Another couple thoughts about ropes....   

In my case I WANT the rope to break!   My wire antennas are Inverted Vee's hanging on a 'yardarm' at the top of my tower (aluminum self supporting tower).  In the event of a tree falling across one of the Vees, I want the tie rope to let go before the wire and certainly before pulling the tower over!  I use cheap light weight cotton at the Vee ends, lasts a couple years.

I use heavy UV resistant stuff to pull the center of the Vees up to the yardarm and that gets replaced abt every 5 years.  It's a P.I.T.A. to drop the tower and I would much rather replace the pull-up ropes than have them break.  To replace these I carefully sew old/new end-to-end and gingerly pull the new up and over the pulleys. 

All this has worked FB for 20 years!  Tower comes down every 10 years for beam cleaning and coax replace.

73, Bill   N2BC

[K3ZS]

I use the double braided dacron available from the usual internet antenna suppliers.   This is the 5/8 diameter stuff.   The only problem I have is animals or birds (?) chew up the excess that I have coiled up to lower the antenna down.    You can put a pulley high up in a tree without climbing it.    Use a slingshot or whatever means, to shoot up some fishing line.   Pull up increasingly heavier gauge string or rope.    Use the last to pull up the pulley with dacron, with the other dacron in the pulley for the counterweight.    I use 1/2 of a cinder block for the counterweight for a 135 ft ladder line center fed doublet. 
The only time I had to repair the antenna in about 10 years is when a direct lightning strike vaporized one side of the copper clad steel antenna wire.

[K6IC]

Hi Tim,

About ten years ago,  used the Marine Polyester three twist rope ... it was cheap and avail cut to order at the local dealer.  Then after a few years,  it tripled in price so switched to the black dacron double braid.  All of this rope has served well and is all still up.

Dacron is a brand name for polyester.  The three-twist rope is a bit better for abrasion resistance than the double-braid,  but in trees abrasion is the killer.

For larger rope ... temp guys for towers,  and large  hauling line etc,  the PolyDac rope is very inexpensive and seems to last about as long as the pure polyester ropes,  but it is usually avail in 1/2-inch and larger sizes.   PolyDac is common at rigging supply/Commercial Marine suppliers.

For going over and through branches,  wire cable or perhaps jacketed Aramid (Phillystran)  type rope section should help resist abrasion.

Nylon works dies in a few years,  PP is junk for UV exposure.

Good Luck,  Vic  K6IC

[WBear2GCR]

The "yellow stuff" is usually Polypropylene - watch ur polys!
What you want is polyester which is also Dacron. Dacron being the trademark of either DuPont or Dow, or maybe Monsanto, one of them...
Stay away from Polypropylene.

I found some Polyester in a pinch at Lowes, but you have to read the labels carefully, they throw in nylon or polypropylene blends, which you don't want.

It is interesting that polypropylene makes a better cap than polyester, but not a better rope! 

               _-_-

[W4EWH]

It just occurred to me: has anyone tried to use a sheath to prevent abrasion damage to haul lines?

I'd imagine that a length of old garden hose would serve well. Do any of you have experience with it?

73, Bill

[Mike/W8BAC]

It just occurred to me: has anyone tried to use a sheath to prevent abrasion damage to haul lines?

Talk to Paul WA3VJB about that. He is the Sheath Mister.

Mike

[W1GFH]

Polyester, dude.

[WA1GFZ]

I put up a clothes line in 1977 using cotton rope. I replaced it 2 years ago and gave it to my Dad to hold his pool cover on. Still hanging in.
Nylon is junk for antennas.

[AB3L]

Try page 22.

http://www.radioworks.com/PDFcatalogindex.html

The Kevlar should last......

http://www.davisrf.com/dacron.php

[WU2D]

Kevlar is cool stuf but it has zero stretch. They are using it for deep sea braided fishing line now. I used it ground fishing a month ago and was amazed. we were 150 feet down fishing for cod and you could feel everything. They used a 20 ft leader so you had some safety stretch.

Mike WU2D

[ve6pg]

..i dont believe kevlar is much good...i am an aircraft structures mechanic, and believe me, kevlar is great for impact, but it wont stretch, and the worst thing is, is draws water in like a straw. there are many aircraft i work on, and if the part is not sealed after trim, etc, water wicks in there in no time. many a leading edge, wing-tip, undercarriage door, etc have had to be scrapped, due to water migration. most operators of aircraft do not know how to repair a composite arid fibre, and do not want to invest in proper care and maintenance...that's when i come in, and either scrap the thing, or they pay me alot to get the thing in proper spec again...sk...

[wb1aij]

  I have tried many types of ropes over many years and believe it or not nylon held up best. I have had some nylon lines holding up wire antennas using pulleys & weights and have gotten over 15 years. Some other ropes like dacron might be more UV proof but nylon is more squirrel proof; they dont seem to like it. Cotton is the worst.

[WA3VJB]

Talk to Paul WA3VJB about that. He is the Sheath Mister.
Mike

Mike/W8BAC saw the assy I have in the trees when he visited out here.

Yes, first of all, it is worth the money to buy the marine grade rope used on sailboat rigging.  (control lines)  I bought a bulk spool to save some money per foot, and further used old garden hose and a pulley system when I put it all aloft. The garden hose protects the rope from abrasion AND provides a cushion to protect the tree branch from "cutting," where the constant tension can actually choke the branch or cause the wood to grow around the line. Sometimes you'll see barbed wire ingrown to a tree trunk, same effect.

Brand name:
NEW ENGLAND ROPES -     002_071_001_530
 
Description

Strong and durable polyester double-braid with a braided core and continuous filament braided cover. The mainstay of New England Ropes' product line. A great balance of stretch, strength, suppleness, abrasion resistance, and cost, which was judged ''hard to beat'' in Practical Sailor testing (December, 1997).

    * Stretch: 2.4% at 15% of breaking strength

Here's the basic plan:

Bow and arrow, a metal hunting arrow with blade unscrewed and lead fishing weight threaded into place. Other end drilled for 30# monofilament fishing line.

Pick your branch, eye the flight line to shoot over the branch AWAY from the direction the antenna will run. This will minimize wasted rope, because you will pull it back toward where the antenna will be connected, and then tie off the cut-end of the rope at ground on the far side of the support tree.

Ready, aim, fire.

Find arrow, clip off and HOLD the fishing line, tie the rope to it, wrap the knot in a layer of tape to keep it from hanging up as it passes branches, and bring it back toward you. When you grasp the rope, now take a piece of old garden hose estimated length to cover the tree branch and any other obstructions the rope would rub against while in place.

Feed end of rope through the garden hose, again grasp it in hand. Wrap some electrical tape to smooth what will become the leading edge of the garden hose and rope assembly when you pull all this back up and over the selected tree branch. The tape keeps it from hanging up, and will keep the hose from wanting to walk off the rope and slide off position.

Tie a sailboat grade pulley² on the end of the rope, making sure the other edge of the garden hose does not interfere with spin. In the picture below, I allowed 5' or so wanting the pulley to be in the clear, away from leaves on the branch.

While still near the ground, now take another run of, preferably, the same type of rope. No sense making a weak link if you can help it.¹  This will be your working line onto which you attach your antenna.  The pulley provides a low friction method of raising and lowering the doublet to trim the wire out, and also becomes the point where tree branch tension can come and go during sway from the wind, and the antenna rope does the moving to compensate, all within the pulley.

PRESTO !!

Once you do this at both ends, you've got years of antenna durability.
Notice here however the tree went and died on me.

That's another project.¹Antennas held up by trees can break in a variety of places. The rope that holds the pulley is as important as the rope that holds the antenna, since if either one of them breaks it's time to shoot another line. You won't be able to retrieve the pulley/rope to thread a new antenna rope through it. All of it on that side has to come down. By comparison, if a wire breaks, there's a chance you can "save" the shoot if the run is still within grasp.

² A sailboat grade pulley will have a weatherproof spool and stainless steel hardware. I recommend the kind with a revolving eyelet that allows the rope to be untwisted once it's all up in the air. Match the spool groove to the size of rope. This minimizes the chance the rope will get hung up and jam within the pulley. For clearance, no knots will be allowed in the antenna line along the length traveling the pulley.

[Steve - WB3HUZ]

Another approach is to use plastic-coated steel cable¹ connected to the pulley. The coating protects the tree similarly to the garden hose, and the cable will just about never break, even if abrasion does occur.


1 - Similar to Lowes Item #: 47635 Model: 597-700, although I usually use 3/16 or larger.