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Old June 19th 09, 12:29 AM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 801
Default lightning protection Coax + Ladder Line

Dave Oldridge wrote:
"Kash J. Rangan" wrote in



If your antenna is balanced, it would probably be better to simply split
the ladder line onto the center conducters of two identical short coaxes
and then run ladder line inside to your tuner. If you MUST ground the
shields that's OK and you can use lightning arrestors on both coaxes. But
remember, no lighning arrestor is as good for protecting equipment as a
foot or two of air. Disconnecting during thunderstorms is solid policy!


If you have a direct hit, a one foot air gap isn't necessarily going to
do you much good, unless the antenna end of the gap is on the ground
surface. (i.e. the wire going from where the coax ends to your
lightning dissipation ground has some non-zero inductance/resistance)

If you're worried about induced voltages from adjacent strikes, then a
good transient suppressor will help, but almost all suppressors have
"let through" voltage that is above the damage threshold for, say, a FET
front end. Depends on what your equipment sensitivity is.

Shorting the input of the radio and tying it to chassis ground.. that
WILL protect the radio.