>
> I've been reluctant to continue this guying thread...
> but this really is slightly different...it's hbx/hbdx related:
Something to remember about the BX through the HDBX series. They are made
from fat stamped steel and like aircraft structures derive their strength
from the shape of the stamped material. Anything that distorts the shape
causes a loss of strength. How much distortion is created by the twisting
it the important thing. That is why they limit the boom length even though
the tower is rated at a rather high figure for wind loading.
The shape factor also makes the proper atachment of guys (when used)
important. I'd not want to resort to the time honored way most of us have
gone in the past, by just looping the guy wire around the leg and I'd guess
that probably happens more with the lighter and less expensive towers.
Guys should be atached using a backing plate and eyebolt if guying hardware
is not provided. Even better would be a backing plate the same shape as the
tower legs that would nest inside. I'd want a backing plate at least the
thickness of the tower leg and about 6" to a foot long.
Properly atached, I don't see how guys would hurt in this case, but the
"loop around the leg" will exert distorting forces on the leg. I'm sure we
have at least a few on there who could calculate the actual values. I
belive those legs are galvanized, mild steel (according to my very old
manual) so the tensile strength figures should be available
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> I saw an hbdx48 come apart from torsional loading from a KT34A...a 16'
> boom. It was guyed at 48', and around 24'. The top section torqued,
> tore, crumpled, and crushed the second section down. From the mid-point
> down, the tower was bent, but not crushed.
>
> And that ended thoughts of a small lpda with a 14' boom on that tower.
> For the record, I don't think the guying hurt or caused the failure...
> just that the tower wasn't very strong to begin with.
>
> N2EA
> jimjarvis@ieee.org
>
>
> _______________________________________________
>
> 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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>
_______________________________________________
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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