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Re: [TowerTalk] Setback requirements

To: <>
Subject: Re: [TowerTalk] Setback requirements
From: "Robert Chudek" <>
Reply-to: Robert Chudek <>
Date: Sun, 2 Sep 2007 18:50:13 -0500
List-post: <>
Pulled quote from below:

"... most of the officials i worked with in FL and here in KH6 
seem to think that towers fall over at the base sideways."

Well I'd better delete these photos from my website real quick:

You'll want to examine photo 040, where the bottom of the tower 
came to rest about 8 feet to the east of the 6-yard concrete base. 
This was a 90 foot self supporting tower with a Mosley PRO-67B 
at the top and a Diamond 144/440 vertical on the mast.

My situation is the exception to Bill's comment "just about every 
tower failure...". It was an intense storm front (downburst or wind 
shear event) that ripped my tower from its base. These high winds 
(100 ~ 150 mph) are not uncommon in the Midwest.

Gary, KØGX in a nearby suburb lost trees and suffered tower damage 
in a similar storm about 2 years ago. His aerometer recorded 125+ 
mph wind speed. His tower stood, although it was bent. Both of our 
QTH's are within an 80 mph wind zone. See page 12 at:  for Gary's saga. 
It includes an interesting photo story how an existing tower base 
was retrofitted for a different brand tower.

Airplanes have been known to get into trouble or crash if they 
encounter wind shear. An onboard detection system was mandated 
for commercial aircraft after 1993. More info here:

I agree that "most" guyed towers will come down within a "semi- 
predictable" circumference of the base. (There's always exceptions.) 
The weight and restraint of the guy wires play a major role in this.

I toured the 1971 Shoreview, MN collapse of a 1200 foot tower and 
the wreckage was contained within a fraction of the tower height. 
I worked one block from that site. The tower was there in the 
morning and disappeared later in the day. Seven workers lost 
their lives in that accident.

73 de Bob - KØRC in MN

----------------------Original Message thread---------------------------

Message: 1
Date: Sun, 2 Sep 2007 00:05:51 EDT
Subject: Re: [TowerTalk] Setback requirements (was "permit in hand")
Message-ID: <>
Content-Type: text/plain; charset="US-ASCII"

In a message dated 9/2/2007 3:25:07 A.M. Greenwich Standard Time, writes:

Is there  an automatic assumption 
that standard engineering practice is questionable  with tower designs and 
that they are likely to fall down?  Nobody  makes that assumption with 100' 
plus high commercial  buildings.

That seems to be the case...most of the officials i worked with in FL and  
here in KH6 seem to think that towers fall over at the base sideways.  A  
hundred foot tower falls over 100 feet.  Yet, just about every tower  failure 
ever seen as a result of hurricanes or seen posts of on the  internet that did 
not happen.
It's hard.....and expensive to argue with ignorance down at city  hall.

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