[Towertalk] Lightning

[Red]

Hi, Talkers;

Some references follow for those who wish to study the subject more.
Add to the list Polyphaser's book, 'The Grounds.'  Industrial
Communication Engineers, LTD (I.C.E.) of Indianapolis, IN also offers a
series of free technical publications on lightning protection and other
subjects that will add to your understanding.

A primary principle of lightning protection is to reduce potential
differences, due to either IR and to L di/dt, to as low a value as
possible.  The potential differences appear among all systems and
equipments connected to that you wish to protect.  In the case of a
typical ham station, that includes the AC power, phone lines, computer
equipment, and other peripherals or systems.  Disconnecting from all
lines and other equipment is the surest way.  Shunting the lightning
transients through multiple paths and blocking them where possible, as
in the ICE and Polyphaser lightning arrestors, are each useful
techniques for reducing differences.

If you choose to disconnect feedlines, disconnect them outside the
house.

Any lightning arrestor, even a spark gap, is better than nothing, but
some are better than others. The spark gap limits potential to thousands
of volts.  Gas tubes suitable for transmitter power limit potential to
hundreds of volts.  Blocking capacitors may be used in RF transmission
lines; they are most effective in the higher HF and above.  ICE is the
only arrestor I know of that uses a blocking capacitor, a gas tube
bypass, and a saturable inductor in parallel with the gas tube for a
really low voltage bypass.

Good references include:

Lightning, Martin A. Uman, 1969; Dover Publications, Inc.  Excellent
overview of observed and measured characteristics and some theory to
explain observations.

All About Lightning, Martin A. Uman, 1971; Dover Publications, Inc.
Very good lay level coverage of lighting phenomena, including the
hazards and protection.  Many references.

Lightning Protection, R. H. Golde, 1973; Edward Arnold, London.

Physics of Lightning, D. J. Malan, 1963; The English Universities Press
Ltd., London.

I recommend Martin Uman's books most highly.

73 de Red, WOØW