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Re: [TowerTalk] Plumbing a Tower

Subject: Re: [TowerTalk] Plumbing a Tower
Date: Sat, 2 Dec 2006 16:02:52 EST
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In a message dated 11/28/2006 8:56:24 A.M. Pacific Standard Time, writes:

>  I played around on the other day doing some  mainteance.  I made up a 
jig out of string to suspend between  the three legs of my Rohn 25G.  I
looped and loosely tied one string  to one leg.  I tied the other end of the
string to the horizontal  brace directly across from that leg and halfway
between the two other  legs.  I did the same for the other two legs and
strings.  The  point at which the strings all crossed each other is supposed
to be the  center of the tower...right? 

    Umm, I'm not sure if I'm following all that but  all you have to do is to 
stand back aways and hold your plumb line in  front of you and look along 
each leg and you'll see how vertical it is.  You're allowed to be out three 
inches in 100 feet so it doesn't have to be  exact. 

>  I may have done this all wrong.  I read  N4KG/K7LXC's comments about 
a tower.  I just used a deep 1/2"  socket as my weight and nylon twine as the
line.  Way too light  compared to N4KG's #20 wire and 5 lb. window sash
weight.  I haven't  yet found a day since hanging the line where the wind is
light enough to  even let the string hang anywhere near the center even 20'
down from where  it's hung.  

Drop the end of the plumb line into a bucket of  water and the wind won't 
blow it around. 

>  I also think maybe I should do the plumb thing in stages  -- in my case, my
tower is 70' and I have two sets of guys.  Should I  plumb from the lower set
of guys to get that portion of the tower plumb,  then plumb from the upper
set of guys to the lower set?   The  plumb line would be shorter and maybe
less influenced by any wind.   

>  Has anyone tried a laser?  Seems like it would be easy  to make up a laser
target jig to place through the tower, then, on the  ground, use a laser in
the center of the tower and aligned to the  vertical.  Anyone done that? 

I think you're making a bigger deal out of  this than necessary. What I do is 
to climb up to the first set of guys with a  little bubble level and put it 
on each leg. You can have someone on the ground  tighten or loosen each 
turnbuckle until you've got it where you want it.  Again, it doesn't have to be 
exactly vertical. 

    Then all you have to do is stand on the ground  next to a tower face and 
just look up. You can tell easily how much it's out  of plumb and which way 
because it'll be pretty obvious. 
Steve     K7LXC
Professional tower services for hams


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