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Old March 14th 06, 08:23 PM posted to rec.radio.amateur.antenna
Richard Harrison
 
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Default Loop In Coax Help Prevent Lightning Induced Surges ?

Steve wrote:
"I wouldn`t think anything but extremely good grounding at the antenna
will do much."

That helps.

Company I retired from had radios all over the world. Most base stations
used Andrew 1/4-wave stainless steel folded monopoles. These were
securely grounded to the tower. The tower had a separate ground rod
connected outside the base to each leg of the tower by heavy strap or
cable. These radios suffered no lightning damage, despite repeated hits.

Kraus has this to say in kis 3rd edition of "Antennas" on pages 719 and
720:
"---a short-circuited lambda/4 section of coaxial line is connected in
parallel with the antenna terminals. This widens the impedance bandwidth
and also places the stub antenna at dc ground potential. This is
desirable to protect the transmission line from lightning surges."

Whenever we could not use a folded antenna with a single-frequency
radio, we connected the shorted stub directly across the antenna and
grounded the coax at the tower top. It works.

Best regards, Richard Harrison, KB5WZI