It seems to me that the issue here is not the design of towers or the
ratings of same: it's of operator error in poorly planning the construction
of his crank-up tower and then leaving it up during conditions that
That one overloaded tower failed is not a condemnation of the tower: it's
condemnation of the engineering, or lack thereof, that went into the
tower-raising process. Poor tower selection and excessive loading will cause
any tower to fail.
Even the Radio Shack tubular towers are good towers: just don't try to
housebracket at 10 feet a 70 footer with a C31XR at the top...
Be that as it may, I've yet to see a properly engineered Trylon system (and
system is the key word) fail. Even here where we do get ice and snow
ps: I'm also not aware of any Trylon crank-ups.
----- Original Message -----
From: "Dave NØRQ" <email@example.com>
To: "'towertalk reflector'" <firstname.lastname@example.org>
Sent: Saturday, June 12, 2004 7:21 AM
Subject: Re: [TowerTalk] Broken Self Supporting Crank Up Tower
> I'm not sure when Trylon started making crank-ups. As far as
> I know, they never have. They make self-supporting
> free-standing towers, as well as guyed commercials towers,
> but not crankups.
> Can they fall down under really bad conditions, or if something
> goes wrong? Yes, of course. So do very large guyed towers,
> including 100'+ ham towers, and 1500' foot commercial towers.
> We've all seen the pictures, and we should plan and build to
> avoid that. But if it gets hit by an F5 tornado or by extremely
> severe ice and wind, all you'll have left is a slab and scrap metal,
> no matter how many and how thick your guy wires.
> Dave NØRQ
> ----- Original Message -----
> From: "Wendell Wyly - W5FL" <email@example.com>
> To: "'Dave NØRQ'" <firstname.lastname@example.org>; "'towertalk reflector'"
> Sent: Friday, June 11, 2004 11:44 PM
> Subject: RE: [TowerTalk] Broken Self Supporting Crank Up Tower
> Trylon makes one of the better self supporting crank up towers and is
> probably the one I would buy.
> That said, a Trylon T600 64 foot tower with 1/2 inch radial ice with 100
> winds is rated for 0.00 sq foot ant load! At 85 mph and 1/2 inch ice the
> Flat antenna max load is only 4 sq ft which is smaller than almost any
> antenna with ice on it. Also rated with a maximum lateral thrust of 116
> pounds and antenna weight of 300 pounds centered and balanced on the
> The antenna cross section in square feet typically far exceeds the ratings
> with 1/2 inch radial ice. This does not include the typical two or three
> feedlines and control lines, rotor, thrust bearing, mast, mast to boom
> plates, antenna switch boxes, etc., that most of us use routinely on our
> towers that also triple in square footage under icing conditions. Most
> antennas are rated in flat square feet and most tower loads are rated in
> round square feet. It may be marketing strategy, but you can't have it
> ways. Trylon shows these calculations at a safety factor of 1.0, which is
> not comforting. At my location in North Central Texas, these conditions
> routinely exceeded several times a year, although this is a "70 mph area
> I have a Catagory C location".
> I believe these are a few of the reasons why several crank up self
> supporting towers have come down in Texas. The tower I saw went down under
> no icing conditions, but high winds and gusty winds, which are even worse
> since few antennas are really balanced for wind loading.
> After thinking about it, I will stick with guyed towers.
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org] On Behalf Of Dave NØRQ
> Sent: Friday, June 11, 2004 9:12 PM
> To: towertalk reflector
> Subject: Re: [TowerTalk] Broken Self Supporting Crank Up Tower
> Though I agree with the intent of the comments, which I think was
> "too many guys overload their towers or don't install them correctly",
> I think that it is quite incorrect to categorize all self-supporting
> in the same way.
> We all probably know of hams that have done shoddy or under-
> engineered installations -- because towers sometimes fall down ---
> both guyed and self-supporting ones, I might add!
> When I put up my self-supporting Trylon T600 64' a few years ago,
> I selected the size, not based on my area's wind speed of 70 mph,
> but on 100 mph. With only 15 sqft of antennas on it, I think that it
> will continue to support itself quite well. And it if does fall, my house
> will probably be missing or severely damaged, in which case the broken
> tower will be the least of my concerns.
> Self-supporting towers are great, even here in Texas,
> IF DONE CORRECTLY. Guyed towers are fine, too,
> IF DONE CORRECTLY.
> Dave NØRQ
> Melissa, TX
> 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.
> TowerTalk mailing list
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.
TowerTalk mailing list