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Re: [TowerTalk] misaligned vertical towers

To: towertalk@contesting.com
Subject: Re: [TowerTalk] misaligned vertical towers
From: K8RI <K8RI-on-TowerTalk@tm.net>
Date: Fri, 22 Mar 2013 16:25:29 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 3/22/2013 1:55 PM, David Gilbert wrote:

Dave has a point. Plumb bobs are rarely hung on a line over 5 or 6 feet long. They are too susceptible to air currents.

In all the years I've worked on towers I can count the days where it was calm enough to even use one on a 10' arm.

Use one about 5' long and sight along the line Two at 90 degrees to the tower will give far more precision than is necessary.

The easiest and quickest is to use a laser transit or level. Of course then the challenge is getting the measuring instrument properly set up

Typical big box stores laser levels and transits are good for about 1/8th to 1/16" in 20 feet which is less than an inch on a 100' tower.

73,

Roger (K8RI)



I truly do not see the quandary here.   You don't need a plumb bob
hanging off the tower ... just hold a plumb bob out in front of you as
high as you can hold it and line the string up with the towers one at a
time from various vantage points.

Dave   AB7E



-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Steve
K7AWB
Sent: Thursday, March 21, 2013 3:00 PM
To:towertalk@contesting.com
Subject: [TowerTalk] misaligned vertical towers


I have two towers up.  A 90 foot Rohn 45 with a 6-el 20 meter beam on
it and
a 102 foot Rohn 25 without anything on it yet.  Both are guyed.  In
putting
them up, a group of us used a Loos tension meter and our eyesight at the
bottom of each tower to make them vertical.

But when I look and align the two towers next to each other by walking
around until they are "next" to each other, one or both are off
vertically
with respect to each other.

How do I figure which is straight and which is off or maybe both are
slight
off?
I really don't want to climb them now in the bad weather and drop a plumb
bob and do not have a survey level.  They are really 135 feet apart.

73
Steve Sala
K7AWB
DN17es
Nine Mile Falls, WA

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