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View Full Version : Weights, ropes, and pullys, or screen door springs?



W1GUH
03-06-2008, 07:28 PM
For dealing with dipoles hung from trees that sway in the breeze.

I've used screen door springs for 48 years and they have always done the job. No antenna came down, no spring broke. And they're very cheap and easy to use.

But I hear a lot of words from "dyed in the wool" believers in weights, ropes and pulleys. What is the advantage over screen door springs?

KL7AJ
03-06-2008, 07:30 PM
For dealing with dipoles hung from trees that sway in the breeze.

I've used screen door springs for 48 years and they have always done the job. No antenna came down, no spring broke. And they're very cheap and easy to use.

But I hear a lot of words from "dyed in the wool" believers in weights, ropes and pulleys. What is the advantage over screen door springs?

If it ain't broke, don't fix it.

W1GUH
03-06-2008, 07:32 PM
If it ain't broke, don't fix it.

One of my more favorite expressions! :D

WB2WIK
03-06-2008, 07:38 PM
But I hear a lot of words from "dyed in the wool" believers in weights, ropes and pulleys. What is the advantage over screen door springs?

::Screen door springs are inductive. If you put one in series with a rope, it will lower the resonant frequency of the rope!:p

W5GA
03-06-2008, 07:49 PM
But I hear a lot of words from "dyed in the wool" believers in weights, ropes and pulleys. What is the advantage over screen door springs?

Consistent tension maybe?

KI6NNO
03-06-2008, 07:49 PM
Springs have a non-linear increase in tension as they are stretched. Weights and pullies provide a constant tension.

For swaying trees, pullies keep the dipole at a constant tension and minimize stretching. Springs will only stretch so far before the antenna is taking up the majority of the tension load - ultimately detuning or damaging it.

Unless you have high winds that might cause the swaying trees to over-stretch the antenna, springs at the anchor points should be fine and simpler than pullies.

KA4EMR
03-06-2008, 08:31 PM
Would an ice storm prevent the spring from doing its job any more so than it would a pulley? Just a thought. I have electric fence insulators on the ends of my dipoles, rope threaded through heavy plastic tubing where the rope goes over the branches, and weights out of reach on the ends. We've had lots of ice storms the past few years; generally the trees sag along with the antenna itself, so it all evens out in the end.

NA0AA
03-06-2008, 10:04 PM
I don't know about others but the springs I've sourced don't have enough tension or extension length to do the job.

I like a counterweight were you can do it, easy to adjust.

KA4DPO
03-06-2008, 10:20 PM
For dealing with dipoles hung from trees that sway in the breeze.

I've used screen door springs for 48 years and they have always done the job. No antenna came down, no spring broke. And they're very cheap and easy to use.

But I hear a lot of words from "dyed in the wool" believers in weights, ropes and pulleys. What is the advantage over screen door springs?


None as far as I'm concerned.

W8ZNX
03-06-2008, 11:27 PM
i have a 80 meter full wave loop
hanging from 3 trees

i do not bother with springs pulleys or anything else

sure at the 75 ft high leg the trees move quite a bit

ant has stayed up for years

how do it do it

slack

thats it slack lots of slack
works great nothing to mess with
nothing to break or wear out

slack

dit dit
Mac

WA9CWX
03-06-2008, 11:35 PM
Actually, I am only using ONE 'door' type spring, if we are talking the same language here.
What I do use, are heavy duty springs. The ones I am NOW using, were advertised as 'Antenna Springs' whatever that means, on eBay.

Five bucks a pair, HEAVY duty, and do an excellent job.

I think the point about the 'constant tension', especially over a significant travel, like in high winds, is valid. I just have not done it. Like Mac said, SLACK. I have a lot of it in my antenna wires. The springs are to avoid a hard 'End Stop' if they take a heavy limb or tree hit.

My antennas DO stay up for years, even in ice and wind, so I am NOT about to change anything at the moment, but I will likely TRY a weight and pully set - up some time.

BTW, ONE of my dipoles is 400' long, and uses a total of 4 springs.

The other is a fan dipole, and uses two springs, and a bungie cord.

In addition, ALL my wire antennas use what I call a 'fuse', a slightly weaker wire, in the 'support system', that offers a KNOWN, easy to access point in CASE of a severe impact.

This is because my dipoles pass under and through a LOT of heavy limbs, and have taken several hits from HEAVY limbs, and the fan dipole has survived two TREES landing on it.
In each case the easy to get to 'fuses' have snapped, leaving the antenna wires 100% intact.

Pulling up the antenna wires with the extension ropes, and re-attaching the fuse sections takes all of five minutes, or less.

IF the antennas actually broke, or came down......RE - STRINGING them could easily take several DAYS, since there is a lot of trial and error in shooting the wires above and through the woods. One half of the 400' dipole, and a good portion of the fan dipole are in and above trees.

Frank

K8ERV
03-07-2008, 01:30 AM
One of my more favorite expressions! :D

Please give Al Gore the credit he deserves.

TOM K8ERV Montrose Colo

KA0GKT
03-07-2008, 04:00 AM
This has been an informative thread...we now know that Mac is a slacker, :D that Frank will spring for anything :eek: , and that Eric puts a lot of weight on his pullys!

I have always used the weight and pully method for contsant tension on the antenna. I custom manufactured my weights using eye-bolts, concrete and coffee-cans (I would suspect that the new plastic variety would work as well as teh old metal cans and not require as much mantenance (paint in the spring).

With the rope and pully method, you can use a long enough rope to facilitate lowering the ends of the antenna for easy feed-point mantenance and still maintain proper tensioning without exceeding the rating of the antenna wire.

K4EEZ
03-07-2008, 03:35 PM
hummmmmmmmmm
is the tree up-side down?
Legs in the air @ 75 Ft ??????????

something not quite right with this picture :D

lol

G4ALA
03-07-2008, 04:48 PM
If it ain't broke, don't fix it.

I hope I am typing an answer here. If not, my apologies.

The tension imparted by springs rises as the support points spread further apart and decreases as the support points come closer together. No problem with that, provided the spring tension never rises to wire breaking point when, for example, the support points are at a exceptional distance from one another.

Weights and pulleys, on the other hand, impart a substantially constant tension which is independent of the distance between the support points. There would seem to be much less risk of wire breaking, provided the pulleys are free to rotate.

I hope this helps,

G4ALA

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