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Re: [TowerTalk] Plugging the top of Rohn 25

To: "KC4HW" <>, <>
Subject: Re: [TowerTalk] Plugging the top of Rohn 25
From: "K8RI on TowerTalk" <>
Date: Thu, 4 Jan 2007 18:32:20 -0500
List-post: <>

>I have a 70' rohn 25 with a regular section for the top section.  What is
> being used to plug the holes to prevent rain water from accummulating in
> the tower legs?

I've seen a number of good suggestions, but...
If the tower base is properly installed water will not accumulate in the 
If you don't live in the frozen north it's even less of a problem.

For looks and peace of mind as well as keeping the spiders and mud dobbers 
out you can tape the leg, covering the bolt holes at the top and use tubing 
caps to close the end. Use Silastic RTV (TM) to hold the caps in place if 
necessary. (then you don't have to run an extension cord up the tower if you 
forgot to seal the legs before assembly.)
According to ROHN, do NOT DRILL holes in the legs or remove the galvanizing. 
They even tell the builder to not drill out the bolt holes which are 
undersize due to the heavy galvanizing. You use taper drift pins and a big 
hammer (5# Engineer's Hammer) to open those bolt holes without damaging the 
So drilling drain holes is not considered a good thing by the company. 
Besides, if drainage is a problem then water will still be a problem below 
the drain holes. Up here the frost line is said to be over 24 inches down, 
but I haven't seen it that deep in years.

However none of this does any good if you live in freezing climate and the 
spiders or mud dobbers build a nest in a tower leg, condensation collects, 
freezes, and splits a leg. I saw an old Aluminum tower where one leg is 
split for 4 or 5 inches about 2 or 3 feet above the bottom from water 
collecting above a spider web/nest. How they got in I don't know as the only 
access point I could find was the split. Possibly they were in there BEFORE 
the tower went up.

When I put my 45G up and had to use high pressure air to blow out the legs 
of each section before putting it in place. With 10 sections of tower I blew 
out a LOT of bees with 120 PSI air. The down wind end of the legs acted like 
a shot gun.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
> Jim/KC4HW
> (June 2nd and 3rd, 2007)


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