TOWER and GUY WIRE LONGEVITY
I'm looking for some imperical data on the
lifetime of (Rohn) towers in non-corrosive
atmospheres.
Last week, I noticed the diagonal braces of some
of my Rohn "35" tower sections were pitted or
rusted. This tower has been up for 15 years at
this location but was bought used. I suspect
it may have been stored horizontally on the ground
at some time.
I also noticed some of the guy wires were showing
signs of rust. I suspect it was some of the "bargain"
guy wire I purchased when I was setting up my station
after scraping together all the cash I could get to buy
the equity on my house / property. The Preformed
Guy Grips still look good with no sign of rust.
Remember my rusted "TV" towers (12 inches across
with 6 horizontal steps (1-1/4 inch dia) and NO diagonal
bracing? They rusted below ground (no cement) and
have heavy surface rust in several places. I determined
they have been in service for over 40 years, 25 at N4KG
and another 15 at a friend's QTH when he was first
amassing his station.
So far, the heavy surface rust seems to have no
deleterious effect on strength or integrity of the
members BUT it is certainly disconcerting to
the CLIMBER and raises thoughts of "how
much longer will this tower be safe to climb?"
(I hit each leg and brace with a hammer or
wrench when first going up after a long absense,
listening for a good "solid ring" before proceeding.)
Anyone have a means of "speculating" on the
length of time it takes for surface rust to degrade
the integrity of tower legs or braces after rust
first appears? Same question for guy wires.
After witnessing the aging / deterioration of my
towers, I always urge my younger friends to
bite the bullet and buy NEW TOWER, GUYS,
and HARDWARE if they want it to last 30 or
40 years. It's no fun contemplating the
rebuilding of your station in your 50's or 60's!
For temporary storing of tower sections, I recommend
placing them on pressure treated 4 X 4 's with some
black plastic laid between the wooden supports to
prevent weed and other growth through the tower sections.
de Tom N4KG
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