[160m] ESD/Lighting Protection

[Tom Rauch]

> Actually I intedt to put Polyphasers and ground the heck
out of everything.

Grounding is 99% of the cure. There isn't a single
polyphaser or other lightning protection device in any cable
here, and I take several strikes a year without any problem
except for occasional cables that blow apart before they
reach the house. No protection device would prevent that, so
I live with it.

> My concern is if I manage to get a fourty foot mast up it
will be the
> highest metal obeject in several tens of square miles.  We
have had several
> strikes in the neighborhood, I've just been lucky so far.
The lightning rod
> would act as a drain for my property and give a strike a
path should one
> actually hit.

Lightning rods don't do anything except act as a target. In
your case, with a metal pole, the change would be very minor
with or without a rod. The biggest improvement comes from
*proper* grounding.

> Another concern is ESD, Electro Static Discharge.  I had a
six foot pipe
> with a 2m 5/8 wave whip on top.  I disconnected the co-ax
from the radio
> during a sand storm but there was enough of a charge
generated that a bush
> of corona three inches long shot out of the end of the
cable into my
> computer and packet modem.

You may need to rethink grounding. The voltage breakdown of
RG58 and larger is normally limited by the connector air
gap. With "N" or BNC connectors it's maybe 4000 volts peak.
With UHF connectors it is about 5-6 thousand volts. The
"spark gap" in a connector will normally arc first.

The only way to have  3" of corona is to have the the shield
isolated from ground with very little leakage. That would
indicate an improperly grounded (not to national code) cable
entrance.  I'd correct that!

> What kind of problems are created with 500' of wire
running right up the
> rear of a radio or will a polyphaser handle a constant
discharge for hours?

If the 500ft of wire is in a shoebox lying on the ground,
almost none. If the 500ft of wire is all entirely vertical,
it's a huge problem.

I'd never depend on a lightning suppression device as the
main protection. The main protection comes from proper
grounding. Commercially manufactured lightning protection
devices are OK, but not on multiband antennas that require
an antenna tuner.  Some are even marginal at handling a KW
into matched loads.

My transmitting system comes in to a DX Engineering antenna
switch box that has relays. When power is off, the
transmitting antennas are disconnected. My control cables
and receiving antennas are connected all the time, however.

I basically never disconnect anything, and have a fairly
large system.
http://www.w8ji.com/my_shack.htm

Grounding is the key.

73 Tom