Just to fuel the fire a little and FWIW:
1) Many years ago when I was in the Royal Air Force in the UK we had a =
75 ft inverted -L antenna at the radio workshops for general listening.
During stormy weather we used to connect an electrostatic voltmeter =
between the antenna and ground. As the storm clouds approached we would =
see the meter indicate an increasing potential usually peaking somewhere =
around 7 - 10 Kv. As the storm cloud passed over the voltage would =
slowly decrease until another black cloud approached. This was not =
neccessarily during storms with lightning activity either.
2) Some years later I was the radio eng. at Muscat Int. Airport in A45 =
land. I had the call A4XFX and had a Johnson Kw Matchbox with a 264 ft =
center fed antenna (600 ohm line) at 80 ft. During the not uncommon sand =
storms tha Matchbox would be arcing over between the capacitor plates =
every 3-5 secs. The arcs were 3/8 to 1/2 inch indicating probably 5 - 10 =
Kv in that very dry atmosphere.
3) On a couple of occasions, During stormy weather, when driving over =
the large hump backed bridges over the intracoastal waterway here in =
Florida I have noticed an increasing loud hiss on the BC band radio as =
I climbed up to the highest point above the water then decreasing as I =
went down the other side. On the two worst occasions it had not yet =
started to rain. The noise became so loud at the top that it generated =
some fear as it was usually coincident with a very nasty looking cloud =
above. I expected a lightning discharge at any moment.=20
These experiences convinced me to take the necessary precautions to =
protect my current solid state front ends whenever hostile weather is =
around.=20
John
AB4ET (G3KQL,A4XFX Etc)
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
|