Date: Sun, 24 Sep 2017 17:15:46 -0400
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] turnbuckle safety wires
<I've been at the top of my 100' 45G when the wind became so strong I
<could no longer work (probably 30-40 MPH)? 40 MPH will bounce you
against the tower and difficult to breathe with the wind 90 degrees to
face on.? There was definitely no slack on the downwind side, nor was
there any sense of movement.? Certainly the tension on the downwind side
is reduced a bit, but it's a long way from being slack.? Whether EHS, or
Phillystran the mechanics should prevent the downwind side from going
slack.? My experience with the array
http://www.rogerhalstead.com/ham_files/Tower29.htm Makes it difficult to
accept the 15 to 18" deflection.? Maybe with a full size 40m Yagi, or
20m? long john
With a telescope (lee side of the house, out of the wind) on a day too
windy to climb the tower, I could barely detect movement of the tower
top with the big array up there.
NOTE: scope and tripod weigh over 140#.? I need to get something
lighter.? A 77 year old back and Arthritis means that scope and tripod
have set in the shop for quite a few years. <:-(.
73, Roger (K8RI)
## I find it hard to fathom that the tower would deflect 18 inches in a 90 mph
basic wind speed.... of course the gusts are a bit higher, like 115 mph.
## read further down, where philly is used..and tower deflects 55 inches !
## I will ask my buddy, who has a 190 ft of rohn 55G and is guyed at 4
levels..
with the top guys being at the 170 ft level. He used .375 fiberglass rod.
14 yagis,
including a 2 el 80m yagi. And the entire tower rotates. He also has a peak
wind speed indicator on top. Anchors out aprx 175 to 180 ft from the base.
His
highest recorded gusts at top of tower have been 57 mph..which is not much.
## Local ham has 150 ft of rotating tower, with philly at 3 levels, but with
4 guys
per level, instead of the usual 3. That reduces the stress by aprx 12%..when
wind is
directly between any 2 guys. Top set of guys at the 130 ft level. But folks
with
rotating towers typ have the anchors out 100% or more... vs the top set of
guys.
Never seen any deflection that I could see with 10 x 50 binocs in a 65 mph
windstorm.
## Has anybody using EHS seen anything near 12-18 inchs of deflection in a 100
mph
wind ? Kurt may well be correct however. K3BU was up towards the top of
his Telrex
big bertha in a 65 mph wind..and it deflected a good 3 ft..... when looking
straight down,
on the down wind side of the bertha... which is enough to freak anybody out.
He was looking
down on the lawn..at the edge of the tower base !
Jim VE7RF
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