> Just wondering what effective measures anyone has discovered to avoid
> this problem, other than completely disconnecting EVERYTHING from the
> transformer when it is not in use: antenna, ground, feedline and all.
Having over 30 antennas is a good test bed for proving reliability of
a system. I can't afford to constantly check and replace resistors
after storms. Despite being in Georgia, with frequent afternoon
thunderstorms, I almost never replace composition resistors that
terminate my Beverages. At the most, I have to change one resistor a
year. The only failures occur when an antenna has a direct hit on a
tree it is attached to, and even then generally only that one antenna
develops a problem. I've actually had wires blown in two without
resistor damage, but I use the correct type of resistors!
If I use a metal film or carbon film resistor, I generally replace it
after every storm, even if the lightning is a mile away. Virtually
all film type resistors, both metal and carbon, will not take much of
a momentary overload.
One thing to remember is virtually all carbon resistors are now film
type resistors. Just because the resistor is a big brown 2-watt
carbon resistor, it does not mean it is a composition type! You
either have to cut a sample resistor open and look inside, or know
the exact manufacturer part number, to know if it is really a
composition resistor.
Use carbon composition resistors (manufactured only on special order
now) or metallic composition resistors (like standard Ohmite OX or OY
series resistors), and constant open-resistor problems will
disappear.
Short of being able to trace the resistor
You have to actually
If you use a composition resistor, it will take almost a direct hit
to damage the resistor 73, Tom W8JI
W8JI@contesting.com
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