1 JAN - 2230 CST
Gentlemen...
It doesn't take a helicopter downdraft or a 15 knot breeze through a 75
foot or higher tower to cause unexpected electrical excitement...
Early in my ham career, I received a heavy jolt when I was attaching a
coaxial line to an aluminum bulkhead-mounted mounted coaxial antenna
lead. The antenna was designed to be DC grounded. But I forgot that at
RF freqencies it was not grounded - and the bulkhead was, at that time,
not grounded.
The weather was very cold and dry with blowing snow crystals in the air.
A check with a voltmeter showed about 200 volts difference between the
center conductor and the shield, and 300 volts between the center
conductor and true earth ground.
Since that day, I have always made sure the downlead wall bulkhead is
well grounded, and all disconnected antenna coax center conductors are
grounded.
Once was enough!
73 - Dick Isely, WD9GIG
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|