I was thinking about picking up a used US Tower from a local ham... but after checking their
It now appears that it would be virtually impossible to get a construction permit for any
of their earlier ham towers based on the lack of engineering data and the fact they are not
rated for any ice loading conditions??? What the heck is going on? Did they have a lawsuit
or other issue?
The standards changed in 2006, specifically:
Wind loading ratings based on IBC 2006 (TIA/EIA-222-G) at 76mph and 90mph 3-second gusts.
Changes did occur to some tower models by some tower mfg. -- construction, installation instructions, antenna sq. feet (wind load) permitted, etc. Some models were discontinued.
You will find EIA/TIA-222 in ALL national building codes for antenna towers (commercial LMR, cellular/mobile, GMRS/CB, Off-air TV, AND amateur radio).
MANY hands were involved in these changes/improvements: Post-Katrina, multiple Florida hurricanes, P&C Insurance industry, etc. Bottom line: Public safety is not a debatable "Home Rule" issue.
US Tower and ALL current mfg. must meet latest EIA/TIA-222 with their current products.
I have said this before, but I will repeat --- Used Towers are dinosaurs without the supporting engineering documents updated for EIA/TIA 222 latest addendum, F or G.
In many cases, the Wonder Pole and other older towers DO NOT meet the requirements.
For the first time, the EIA/TIA-222-G code will line-up with national building codes, most notably the 2002 version of the International Building Code (IBC).
If you haven't seen a copy of this code, it outlines all of the possible code-related items and refers the reader to several references of other codes, such as NEC (National Electrical Code) and NFPA (National Fire Prevention Assn.). The underlying reference to which the IBC deals with telecommunications towers is called ASCE-7. ASCE is an acronym for the American Society of Civil Engineers and ASCE-7 deals with all things structural, including towers. The latest version of ACSE-7 (2002) will ultimately refer you to what will be the EIA/TIA-222-G standard.
If you have recently constructed a tower in a state or local jurisdiction that has adopted the code, you may have been asked to provide a structural showing compliance with a specific version of the IBC. Note that the previous version of the IBC (2000) references the EIA/TIA-222-F version.
Last edited by W9GB; 07-08-2012 at 10:20 PM.
We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths. -- Walt Disney
I have a U.S. Tower and have installed several of them.
They're good towers, but seems as though they're covering their butts for some reason. I have no clue if they were sued or anything like that.
Fact is, with heavy ice loading there isn't much that can be guaranteed. Ice can make a 40 lb tribander weigh 600 lbs, and take its wind load from 4.7 s.f. to 9 s.f. overnight or sooner.
I think U.S. Tower, like most tower manufacturers, sell a lot more to commercial interests than they do to hams and probably don't care a lot if you buy a tower, or not. I remember contacting Rohn about this 30 years ago and their national sales manager said the "ham" market was much less than 1% of their total market and if it all went away, they really didn't care. No impact on the bottom line.
A government which robs Peter to pay Paul can always depend on the support of Paul.
-- George Bernard Shaw
With the engineering data pulled from the website I'd wonder how anyone would be able to get
a permit to install one of these towers? That's the problem. It looks like US Tower has
pretty much removed themselves from the ham market. There aren't a lot of choices