I need to guy the tower because I've exceeded the tower's design limit by a
factor of 3.7. If my two yagis were both mounted one foot above the thrust
bearing I'll be below the limit. However having one yagi at one foot above the
bearing and another one seven feet above the bearing generate enough bending
moment that exceeds the tower's limit in the retracted position (3,700lb-ft vs.
1,000lb ft. at 122mph wind speed). I didn't do my homework before I put
everything in. Hindsight is always 20/20. Getting a new tower is out of the
question. So I have two choices, do without my 40m yagi or guy the tower. I
read the UST FAQ document and it does say it's ok to guy the bottom section of
the tower. There are no details on how to do it. I didn't go with a
traditional guyed tower because I don't have enough space for one. However I
do have space to guy the bottom section of my retractable tower. I get extreme
winds here (>100mph once or
twice a year, >70mph ten days a year). UST did the calcs. for me at 122mph
and they said the tower could handle 15.6 sq. ft. when retracted. However my
Skyhawk yagi is rated at 8.5sq. ft. which is too optimistic. The true number
is more like 12.2 sq. ft. projected. 8.5 sq. ft. is most likely an 'effective'
windload for flat members. The TH-11 is about the same size as my Skyhawk and
it's rated at 12.5 sq. ft. My F12 D240 is rated at 5.8 sq. ft. projected. I'm
unsure if the 5.8 figure is optimistic or not but that's what Mark at F12 told
me. So in a nut shell I don't want to lose my 40m yagi and that's why I'm
looking into guying the tower.
From: "K7LXC@aol.com" <K7LXC@aol.com>
To: firstname.lastname@example.org; email@example.com
Sent: Sunday, October 7, 2012 4:06 PM
Subject: Re: [TowerTalk] Guying a TX-472 bottom section
> I'm looking for someone who has guyed the bottom section
of a TX-472.? I need a guy bracket and the Rohn standard bracket wouldn't fit.?
I want to hear from those who has guyed the same or similar tower.?
And the purpose of this guying is...?
What does the factory say about guying the bottom
section? I don't think they do. Unless there's some compelling reason to do so
and I can't think of any), guying the bottom section is unnecessary. The tower
is designed to be free-standing. If the factory doesn't say to do it, don't do
The LXC Prime Directive is to "DO what the
manufacturer says." The opposite is also true - "DON'T do what they don't tell
UST Factory authorized installer
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