RadioIR at charter.net
Mon Feb 6 17:20:15 EST 2006
Sounds overloaded to me, but you should do the calculations to be sure.
I have an HDX555 with a 4 element SteppIR 2 ft up, and an XM240 9 feet
above that, and a 20 ft mast. That's 16.4 sq ft (antenna plus mast) on a
tower rated for 29.5 sq ft at 70 mph, but this load max'es out my tower
at 74 mph average with gusts to 95 mph. The HDX is rated significantly
more than the TX.
For some free software to make these calculations go to
and download the file labled TRANVITY.ZIP. Also download the following
pdf file which gives some good explanations of the calculations.
Bill Ogden wrote:
>>His 55 foot TX-455 US Tower is on the verge of collapsing down. The
>>owner just noticed that two out of three legs of his tower just broke
>>down. The legs snapped just above the mounting ears where the tower is
>>fastened to the "T" mounting plate. We suspect that some 90 km/h wind
>>gusts we have had here in Toronto last week may have been a contributing
>>The tower is currently nested and the antennas are still on top of it.
>>It is basically holding on only one of the remaining legs and a few
>>cross braces. It was installed brand new in 1990 and it had a 2 el GEM
>>Qubical Quad installed ever since. In 2003, owner replaced the short
>>mast with a 22" cromoly nested about 3" inside the tower and added a
>>home made rotary dipole for 30/40 m at about 10 feet above the Gem
>>Quad. The dipole is a modified Cushcraft D3W warc dipole.
>>From this description, the very heavy (I assume) cromoly mast extends
>about 19 feet above the tower. I assume this adds greatly to the turning
>moment on the tower, even with relatively small antennas on it. Does
>this exceed the tower specs? (I have a TX-455 with a 10-foot mast, with
>about 5 feet above the tower. I have been thinking about a slightly
>longer mast so I can mount a 30/40 rotatable dipole either above or below
>my 3-element SteppIR.)
>Bill - W2WO
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>TowerTalk at contesting.com
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