25 and 45G can be tilted up in substantial lengths with sufficient
guying and tension. Depending on weight and antennas, several sections
of 25 or 45G can be between the guys.
45G can be tilted up and still set on a pier pin. With a bit of
planning, it's not all that difficult.
Adding guys to a free standing tower is asking for trouble.
With the pier pin base on a guyed tower, torsion is no longer a tower
problem and is addresses with the guys. Usually using a star guying setup.
73
Roger (K8RI)
On 10/15/2014 12:02 PM, Richard (Rick) Karlquist wrote:
To clarify:
I didn't say not to have a fixed base on a guyed tower.
Rather, the base has to be larger than just a 6 inch
thick slab to keep it from sinking into the ground,
unless a pier pin is used. For various reasons, I
don't want to use a pier pin, and instead will make
the base large enough. OTOH, the needed base is
much less than it would be in the self supporting case.
So, you ask, why would I use sections intended for
self supporting applications in a guyed configuration?
Very simple. I want to assemble the whole tower with
antenna, etc on the ground and tilt it up. That kind
of thing has been done with Rohn 25, etc, but works
better with sections designed to be self supporting.
Dead weight and strength/weight ratio, and stiffness,
normally of minor importance once the tower is
vertical, are major issues during tilt up.
Rick N6RK
On 10/15/2014 7:57 AM, ve4xt@mymts.net wrote:
I'm curious, Rick, if your engineer addressed this question: to what
extent does the warning to not have a fixed base on a guyed tower
(use a pier pin instead) apply to the question of guying a
self-supporting tower (which by design would have a fixed attachment
to the base)?
Seems the issue of torsion would be the same, yes?
From an initial design perspective, if you were planning a guyed
tower, would it make sense to pay extra for a freestander?
It seems the question of guying applies best to attempts to increase
load factor of an existing freestanding tower.
73, Kelly
ve4xt
--
73
Roger (K8RI)
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