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Author Topic: Inverted V end weights?  (Read 1491 times)
N4NYY
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« on: October 31, 2011, 09:09:58 PM »

I am about to order supplies for a 5 band trapped vertical in an Inverted V. Using a 3 pulley (apex and 2 ends), what sort of weight am I looking at for keeping the wires tight? Are we talking like several 8 oz fishing sinkers, or a milk jug full of sand?

This is my first wire antenna and 1/2 homebrew (other half are commercial traps).
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WB6BYU
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« Reply #1 on: October 31, 2011, 09:21:42 PM »

How heavy are the traps?  the wire?  How steep of a slope to the wires?
How much sag are you willing to tolerate?

I never plan to put more stress on a wire than I can easily pull with one hand.
I generally use 5 - 10 pounds, but that is with light wire.  In one house I had
some old sash weights that were just about right.

The milk jug full of sand (or water) is a good start - they will break down in
the sun before too long, but you can adjust the weight and see how much
you need for a more permanent solution.

(At the moment I have a couple lengths of angle iron hanging down the middle
of my tower.)
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N4NYY
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« Reply #2 on: October 31, 2011, 09:23:32 PM »

Unadilla traps. I think there are 8 oz each. I was going to use copperweld.
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W3LK
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« Reply #3 on: November 01, 2011, 12:04:57 PM »

I am about to order supplies for a 5 band trapped vertical in an Inverted V. Using a 3 pulley (apex and 2 ends), what sort of weight am I looking at for keeping the wires tight? Are we talking like several 8 oz fishing sinkers, or a milk jug full of sand?

This is my first wire antenna and 1/2 homebrew (other half are commercial traps).

How do you make a vertical into an Inverted-V? <gg>
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WB6BYU
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« Reply #4 on: November 01, 2011, 12:34:56 PM »

Quote from: N4NYY
Unadilla traps. I think there are 8 oz each. I was going to use copperweld.

That's a fair bit of weight in each span.  You might need as much as a cinder block
on each end if it is fairly flat and designed for 80m or 160m.  On the other hand,
if the legs slope down at 30 degrees from horizontal (so the center support takes
a lot of the weight) and the lowest band is 20m, a few pounds may be adequate.

As a rough estimate for a horizontal antenna, the ratio of the sag to the span
distance is about half the ratio of the antenna weight to the counterweight weight.

So if your span was 80' to tie off one leg, and the wire + traps + insulators + rope
on that leg weighed 5 pounds, a 20 pound counterweight would give 10' of sag.
[sag = 1/2 * 80 * (5 / 20 ) ]  That assumes that all the weight is suspended in the
center of the span.  A bit of geometry can give you an answer for an inverted vee,
depending on the angle.
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N4NYY
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« Reply #5 on: November 01, 2011, 12:53:54 PM »

Quote
How do you make a vertical into an Inverted-V? <gg>

Lon,

I finally got sick of the 5BTV in the swamp. I had to go and cut the growth back twice each year. However, the nail in the coffin was that the antenna was located at the edge of my property line. That lot behind me was sold and house is about to be completed. So, I decided go with an antenna closer within the property lines.

I conferred with W8JI, and was advised to set up an inverted L with some radials and a remote tuner. That idea was killed by the Z-11 being obsolete. I called LDG, and they do not have immediate plans for replacement. The remaining 2 tuners on the market are MFJ (suffers from quality problems), and a $600 high end unit. That $600 was too steep for a tuner alone. Down the road, I would still like to go this route.

In the meantime, the trap-vertical was my best option.
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N4NYY
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« Reply #6 on: November 01, 2011, 01:20:26 PM »

WB6BYU,

I should not have any problem doing a 90. I did an Pythagorean calculation and I actually have enough room for 73' on one side, and 73-92' on the other. The actual legs are only around 44' or so.
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AC5UP
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« Reply #7 on: November 01, 2011, 02:25:34 PM »

Make sure the last 10' to 25' of rope nearest the ground is WIRE ROPE.

Might not be significant in your part of the world, but grass fires are a regular part of life out here west of the Missus... Misass... Messus... the big river. Wire rope secured to an iron pipe can survive a burn.

As for weights, I tend to have scrap pipe sections in the 1 1/2" to 2" flavors that carry some weight in 3' or longer lengths. Iron pipe also has the advantage of being able to ride a wire or rod. Visualize a 10' pipe with 2' in the ground, guyed opposite the antenna, the antenna line runs through a pulley near the top of the pipe to a 2" counterweight threaded over a 1" pipe. The counterweight is free to ride up and down but can't swing in the breeze.

Next time you're at the hardware store price out some iron pipe. I think it's cheap and easy to work with. As for wire rope, the thinnest stuff on the shelf is stronger than what you need. Just be sure it's galvanized or otherwise rust resistant.
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N4NYY
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« Reply #8 on: November 01, 2011, 03:31:40 PM »

Nelson,

Good idea. May I can pick up a couple 10 lb barbell weights. I have to try and get these pulley systems up.
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KC9TNH
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« Reply #9 on: November 02, 2011, 12:11:13 PM »

I had an old set of of 5-lb baby barbells, used for hand-curling during some previous wrist therapy, acquired from the local $/liquidator store.

It's just weight.  You are unlimited by your imagination - and then limited by any aesthetic considerations you may have (or thrust upon you).
I thought about a couple of ugly ceramic owl lawn ornaments to drive the crows nuts, then remembered I like to sleep-in a couple times a year.

 Grin
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73
Wes -KC9TNH
"Don't get treed by a chihuahua." - Pete
KB3MDT
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« Reply #10 on: November 02, 2011, 01:18:43 PM »

Hi,
   I use bricks.  I wrap each brick in a little wire (20 gauge galvanized steel?) as if I was wrapping a present.  I make a loop in the wire where one would normally put the bow.  I then tie the antenna rope to the loop.   This works for my fan dipole.

KB3MDT. 
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W1JKA
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« Reply #11 on: November 03, 2011, 03:14:12 AM »

     I use the old window sash cast iron counter weights,eye already in the end and shape doesn't
get hung up.
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K8AC
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« Reply #12 on: November 03, 2011, 05:01:38 PM »

Never thought the weight business was better than what I've used for many years.  I use galvanized screen door springs a few feet beyond the ends of the wire and the lines are tied firmly to something on the ground.  The springs allow for a couple of feet of movement and for a heavy length of wire antenna, two springs can be used in parallel.  There's no reason to try and pull the slack out of the wires. 
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KW9W
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« Reply #13 on: November 04, 2011, 06:11:37 AM »

No weights! There's plastic dogbones (made for antennas) on the ends, and a section of thin white rope tied to the dogbone, and also tied to something else that is anywhere from several feet from the end to 20' away.

John - KW9W
« Last Edit: November 04, 2011, 06:13:23 AM by KW9W » Logged
N4NYY
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« Reply #14 on: November 04, 2011, 06:39:52 AM »

Quote
No weights! There's plastic dogbones (made for antennas) on the ends, and a section of thin white rope tied to the dogbone, and also tied to something else that is anywhere from several feet from the end to 20' away.

We were not talking about tying it to the end of the wire. We were talking about the end of the rope (after the dogbone). And I am using Dacron.
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