[TowerTalk] Lightning... and pointed rods!

[David Jordan]

Mike,

When AM auto radio first came out the receive antennas were first
mounted underneath the frame of the vehicle...later they were moved to
the top of the vehicle. There was a static build-up of a few hundred
volts on the receiving whip when the vehicle was driven over 25mph.
This static build up caused significant noise on the AM receiver.  The
fix was to install a small sphere at the top of the whip. The sphere
effectively dissipated the static build-up reducing the popping noise in
the ca'sr radio. Some folks mistakenly thought the advance was for eye
safety...

Many years ago, I think it was SWAN, a beam went into production with
loops of wire at the ends of the elements. Not sure if the loops were
for additional capacitance (for shortened elements) or to reduce static
noise or both.

Also have seen commercial beams  with spheres mounted at the ends of the
elements.  Perhaps for the same reasons described above.

On 160m it's really easy to hear the snow storms coming out of the
midwest.  Perhaps I'll borrow a few of my wife's stainless steel mixing
bowls, put them together to form a sphere and mount one on each end of
my dipole to see if the snow static is reduced ;-)

HAVE FUN,
dave
WA3GIN


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