Stuart, I have been using spark plugs for 25 years or so.
I was trying to find a picture somewhere but couldn't, so I will dig mine
out of the junk box and make a photo.
My spark plugs were purchased from Annecke, years ago.
He sold them as single, or "matched pair" (hi).
I always insert the pair in openwire feedlines.
In addition, Annecke sold high voltage relays that were built into
water-proof enclosures.
You mount these outdoors away from the house.
The relays ground each side of the openwire when not in use.
I have all of this but unfortunately you can't buy it anymore.
Annecke has been an SK for 15 years and his business simply closed after he
passed away.
However there is nothing special about his stuff. It is simple enough to
home-brew.
Come October or November, when the wx turns bad, I plan to go back to work
on my web site.
(For now I'm playing with antennas outside).
I have a section of my web dedicated to Annecke's wonderful products, but it
is only about 15% complete.
Eventually I'll have pictures and schematics of everything posted there,
including these static-protection products.
The Annecke section is here:
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Stuart
Rohre
Sent: Wednesday, July 31, 2013 3:17 AM
To: tentec@contesting.com
Subject: Re: [TenTec] OT: Openwire/Window Line and Bad Wx
Usually a double pole knife switch used to switch antennas would have a
double throw. That is in one direction it made the circuit tot he radio, in
the other direction it either connected to the receiver, or to ground fot
dissipate any static build up on the antenna.
To protect parallel line feeder, you can take a pair of used spark plugs and
put the points close enough to not arc over with your transmitter's maximum
power, but to still arc over if static build up happens. Wind induced
static can build quickly to over 600 volts and reach thousands of volts in
the presence of a nearby lightning event.
There are also telephone type line protectors for nominal 600 ohm lines.
The modern versions use a Zener diode on each line leg, that breaks over
to conduct to a ground rod, at a peak voltage higher than the radio RF wave
voltage. The diodes that come for telephone service may not be as resistant
to constant RF, and may need to be changed to a higher break down diode.
-Stuart
K5KVH
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