Several years ago, I was quite fortunate to attend a seminar about lightning
protection presented by one of GE's lightning experts. He had worked for
their mobile radio group in Lynchburg, VA. Unfortunately, I can't lay my
hands on the notes I took, or remember the man's name. (I do remember that
his surname was the same as that of a popular folk singer--maybe
"Guthrie"--funny how the mind works! I'll probably find my notes or
remember his name right after I push the "send" button.) He was a ham, and
I believe he became an SK a few years ago.
One of his stories (he was a most delightful speaker) was about working in a
lightning-prone area where some appliances (primarily air conditioners, as I
recall) were being damaged or ruined by surges induced by lightning. He
hypothesized that tying overhand knots in the power cords would provide good
protection. Interestingly, as I recall, he also suggested six knots. As I
recall (I hate to keep saying that), he said that they never lost another
air conditioner after that.
He showed us a power cord that had been taken from an AC unit after a storm.
It had a half-dozen knots in it and several of them obviously had been
"fried" by high voltage--melted insulation. etc. He said that the AC unit
had survived.
Knots in power cords? You betcha!
73
Jim, W3WV
________________________________
Jim Wilcox
----- Original Message -----
From: "Red" <RedHaines@centurytel.net>
To: "James" <jameswarren@swbell.net>; "Towertalk" <towertalk@contesting.com>
Sent: Saturday, 12 July, 2003 09:48
Subject: Re: [TowerTalk] Re: lightning suppression on cable
A high percentage of the energy in a lightning strike is in the spectrum
under 1 MHz. I don't think tying knots in the line will impede it much.
73 de WO?W
James wrote:
>>I get both TV and Internet via TV cable. It is the last conductor coming
>>into my house that is not protected by a lightning or surge suppressor, or
>>disconnected when not in use. Can anyone suggest an appropriate
>>suppressor for this purpose that will pass both TV and 2-way Internet
>>signals (low HF to high UHF)?
>>
>>
>
>I've used commercial grade coax lightning arrestors for commercial
>two-way and cellular antennas. Very expensive, but the work and are
>almost invisible when you do a TDR line sweep, even at 1900 MHz.
>
>At home, I tie six knots in my power, control, and antenna lines before
>they come into the house. Eveything is inside a metal box WELL grounded
>with several eight foot long grounding rods. The high "frequency" of
>a lightning bolt (actually the DV/DT) has trouble even making a right
>angle bend, much less an entire knot. For this reason, ground wires
>need to be routed to a ground with no turns; but if neccessary, a gentle
>curve..
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