[Top] [All Lists]

Murphy in ARRL/CW

Subject: Murphy in ARRL/CW
From: mikemr@microsoft.com (Michael Mraz)
Date: Tue Feb 23 18:48:12 1993
My own laziness almost destroyed my TH-11 early Saturday morning (0100 local).
I had just cranked the 52-foot crank-up tower down to get the beam out of the
way so that I could fly the 160m 1/2-wave-balloon-vertical. The tower's main
lift cable snapped soon after I returned to the shack to get some tools.
Although the tower can nest to 21 feet, the top of my chimney is at 30
feet. The sound of the antenna hitting the chimney and roof, driven by
the combined weight of antenna and two tower sections (>500 lb) was
sickening to say the least. It sounded like a small airplane had crashed
into the house. The antenna hit on the reflector end, and it appeared that
the boom (reflector end), 20m and 17m reflectors, 20m and 15m driven
elements, mast, and thrust bearing were toast. The carbon steel mast
(2" dia, 1/8" wall) had been bent at about 15 degrees at the thrust bearing.

After sunrise, and after the night's snowfall had melted, I went up on the
roof to inspect the damage. Amazingly, only a few shingles were damaged. The
long driven element in the log cell had been bent by the impact force, and
the two element halves were curved symmetrically in different directions.
The long element (20m reflector) was fine, and the only damage to the 17m
reflector was a bend at the boom-to-mast bracket (this was the element that
hit the chimney).

On Sunday, I titled the tower down and took the antenna apart. Amazingly, there
was no damage to the boom, and only minimal damage to the 20m driven and 17m
reflector. The mast was history, but everything else is just fine.

The sad thing is, I have had a new lift cable sitting around for 2 years. When
the tower was down last summer (to install the TH-11), I was in a hurry 
and didn't
replace the cable. As the guy at Hy-Gain said, "When I ship you a new cable,
it's for a good reason!!"  See you all in the CQWW 160/SSB  73  Mike  

<Prev in Thread] Current Thread [Next in Thread>
  • Murphy in ARRL/CW, Michael Mraz <=