Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!think!ames!ucbcad!ucbvax!cbosgd!cwruecmp!neoucom!wtm From: wtm@neoucom.UUCP (Bill Mayhew) Newsgroups: sci.electronics Subject: Re: Lightning Rod Problem Message-ID: <616@neoucom.UUCP> Date: Sat, 4-Jul-87 14:08:30 EDT Article-I.D.: neoucom.616 Posted: Sat Jul 4 14:08:30 1987 Date-Received: Sun, 5-Jul-87 07:38:44 EDT References: <204600003@prism> Organization: Northeastern Ohio Universities College of Medicine Lines: 31 Summary: Radio design manuals advocate use of sphere on tip Several books I have on antenna design recommend using a small metal or even plastic ball on the tip of whip or pole type antennas. The two books I looked at don't show mathmatical proof, but claim that the increased surface area of the ball makes it easier for static to dissipate. The claimed result is that generation of small sparks is reduced, thus cutting down on the amount of crackle emitted from the speaker of a receive attached to said antenna. Supossedly, this is especially helpful on car radio antennas. I once had a car where to little ball on the tip fell off during the time I owned the car. I didn't notice any difference in the performance of the radio after the tip fell off. Since the purpose of a lightning rod is to dissipate static that could attract a lightning bolt. It seems that the increased surface area of a ball-tipped lightning rod would be helpful. Does anyone out there have any information on dealing with lightning strikes in *very* tall buildings. On a building several hundred feet tall, lightning hits would essentially be assured. I've seen some commercail radio transmitters with quite ealborate spark bussbars and gas filled tubes, etc. I've never had the chance to take to the engineer at such a facility about lightning, but I'd imagine that radio and TV towers are also routinely hit. --Bill (wtm@neoucom.UUCP)