The ROHN catalog is very specific about not drilling galvanized tower legs.
They don't even want the bolt holes drilled out. If the bolt doesn't fit
they direct the builder to use "taper pin punches" of the proper size to
enlarge the holes until the bolts just slide in. They also direct us not to
drive bolts in.
Any hole drilled removes the galvanizing at that point.
BTW, I have 10 sections of 45-G up. That is 60 bolt holes. I had to drive
taper pin punches into almost every one to get the bolts to fit.
Depending on conditions some towers may last indefinately with holes drilled
and others may rust out in a hurry. Here in Lower Michigan I've seen both.
I really can't say why "in some cases" the tower rusted out and in the
others it didn't. Then there are most of the cases where I can see where the
rust started in a weld, hole, or base with poor drainage.
There are many of the old steel, ungalvanized TV towers out there that are
not much more than a coat of paint holding the rust together. OTOH some of
them are still in good shape and holding up tribanders which are a far
larger load than the tower design specs.
<snip>>
> Instead of a gravel base at the
> bottom of galvanized towers, I have
> always used 2 pound coffee cans filled
> with gravel surrounding each leg, with
> the bottom of each leg resting on gravel
> ~3" above the bottom of each can.
I've just found it far easier to throw in a few shovel fulls of sand and
then about a dozen of crushed rock.
> I puncture several holes in the bottom
> of each can to allow water to drain. The
> steel eventually rusts leaving hardened
> concrete surrounding 3 gravel plugs.
> Why waste the expense and physical
> energy to completely cover the entire
> base area with gravel? Call me cheap
> and lazy! :-)
I'd not have the ambition to make up the cans to fit the legs<:-))
A lot does depend on your location. Here a couple wheelbarrows of crushed
rock or pea gravel would cost little and you just dump them in the hole.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> 73, Bill W4ZV
>
> P.S. Peter, you always have exceptional
> ears to hear my QRP to a piece of wire on
> 20m. Whatever you use works very well!
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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