[TowerTalk] US Tower 72 ft crank up grinds to a standstill

[Barry Merrill]

Since I knew it was overloaded, I never intended to leave it up
when storms were headed this way, and only got caught on a few
contest weekends when I was not paying attention to weather.

Thanks for making your post a private message, so I could have
chosen to not 'fess up, but I am morally obliged to answer you
excellent question, and to confess.

73

Barry, W5GN

-----Original Message-----
From: Paul Dulaff <pdulaff at embarqmail.com> 
Sent: Thursday, May 28, 2020 2:44 PM
To: Barry Merrill <w5gn at mxg.com>
Subject: Re: [TowerTalk] US Tower 72 ft crank up grinds to a standstill

Barry

If this is the UST 572 tower then payload is rated to 350 lbs. Antenna wind area rating for this tower is 14.1 sq ft. at 1 foot above the top of the tower. Your configuration has 30 sq ft. with 12.6 sq ft. of antenna area at 20 ft above the top of the tower. Clearly way overloaded to the IBC code. What wind loading value did you determine this configuration could withstand before needing to lower ?

Paul - W2NMI

----- Original Message -----
From: Barry Merrill <w5gn at mxg.com>
To: towertalk at contesting.com
Sent: Thu, 28 May 2020 12:07:57 -0400 (EDT)
Subject: Re: [TowerTalk] US Tower 72 ft crank up grinds to a standstill

"From what I understand, UST rates the 72 foot crank up towers at
 200 lbs antenna(s), rotor and mast, bearing etc weight with
 22 lbs of cable weight, 222 lbs max vertical dead weight."

My UST 72 was installed in 2003 with a 9x9x9 concrete base, The tower has 

 OB16-3  Triband  132
 CAL-AV  40       163
 Cable/Rotator     50
                  345 pounds

I did have the tower fully extended a number times early on, lowering it for most storms, but several times I misjudged the storm's arrival and it took a beating, and then a final time when I was unable to lower the tower as it moved in the wind convinced me to give up the extended height, and since then it's been about 10 feet extended, enough for the Cal-AV to be at 30 feet, (which is still an amazing performer, beating locals with stacked 2 el HyGains) and the OB=16-3 at 50 feet and the tower positioned so the rotator can be removed.

But those several instances of extended with wind have left their mark.  We had added a pretty stone patio across the top of the base and around the base area and now all four sides have broken and appear to have moved about 2 inches vertical on each side!

I surely can't complain to UST with my overload!!

73

Barry, W5GN


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