]
On Behalf Of Guy Olinger K2AV
Sent: Saturday, July 28, 2012 1:06 AM
To: N2TK, Tony
Cc: topband; donov...@starpower.net
Subject: Re: Topband: Spark gaps
What is the condition of your 160m radials after the lightning strike? 73,
Guy.
On Fri, Jul 27, 2012 at 7:48 PM, N2TK, Tony tony@verizon.net wrote
Bob, that an excellent idea!
Dave WX7G
On Jul 28, 2012 6:06 PM, Robert Briggs vk...@bigpond.com wrote:
Has anyone thought about using two trailer towing balls set up for a
spark gap? I use this on a 90 foot insulated mast in a very lightning
prone environmentTo date (25) years, with
be shielded from rain and
insects. The gap should be adjustable, and it should be set to about the
thickness of a credit card (1 to 2 mm).
73
Frank
W3LPL
Original message
Date: Sun, 29 Jul 2012 11:33:07 -0600
From: DAVID CUTHBERT telegraph...@gmail.com
Subject: Re: Topband: Spark Gaps
happening.
Carl
KM1H
- Original Message -
From: donov...@starpower.net
To: 160 reflector topband@contesting.com
Sent: Sunday, July 29, 2012 4:18 PM
Subject: Re: Topband: Spark Gaps..
Trailer hitch balls should work fine as a lightning arrestor. Typically a
trailer hitch ball has
Thank you to all the email's received re my use of trailer balls for a
spark gap..It is a simple answer to a big problem and it works..
It pays to think outside the box at times when presented with a problem
and be a bit innovative..
I also use a trailer ball at the bottom of the 90 foot mast
: Re: Topband: Spark gaps
What is the condition of your 160m radials after the lightning strike? 73,
Guy.
On Fri, Jul 27, 2012 at 7:48 PM, N2TK, Tony tony@verizon.net wrote:
As a side note, last night when the storm came barreling in with very
strong
winds I was watching the tower
Has anyone thought about using two trailer towing balls set up for a
spark gap? I use this on a 90 foot insulated mast in a very lightning
prone environmentTo date (25) years, with many direct hits, I have
sustained no damage...Mast is located 20 feet from my lounge room..
-boun...@contesting.com]
On Behalf Of donov...@starpower.net
Sent: Friday, July 27, 2012 5:26 PM
To: topband
Subject: Re: Topband: Spark gaps
This link shows the base of a typical AM broadcast tower, with two hard
steel balls used as lightning protection. At kilowatt power levels its
Has anyone looked at, or looked for, cheap electric fence gaps??
My system copper pipes near tower legs work great for me on rigid towers, I
can bend them so they spring away from the tower and then slide an inner
pipe in or out to set gap distance. I'm thinking of gaps for wire antennas.
Yes a direct hit should vaporize a spark plug. For a 100 kA hit two 1
diameter rounded steel balls may survive.
Note that Ross Engineering uses carbon balls on their spark gaps.
At 50 kA/us every inch of wire will have a voltage drop of 500 to 1000
volts, so very short wires are in order. Wide
: Topband: Spark gaps
To: topband topband@contesting.com
Has anyone looked at, or looked for, cheap electric fence gaps??
My system copper pipes near tower legs work great for me on rigid towers, I
can bend them so they spring away from the tower and then slide an inner
pipe in or out to set gap
You can get chrome steel balls too and they are *very* hard (usually
used for ball bearings). You have to drill them with solid carbide
drills. I don't think it would be possible to thread the holes using
normal taps though.
-Bill
[snip]
Very hard steel balls such as carbon or tungsten are
I don't think carbon balls are suitable for lightning protection. Think of
the voltage drop that would appear across each ball during a direct hit. I
think they would vaporize.
At http://www.rossengineeringcorp.com/hv_spark_gap.htm lightning is not one
of the applications mentioned for their
Google carbon ball gap lightning.
Dave
On Jul 27, 2012 9:33 AM, Mike Waters mikew...@gmail.com wrote:
I don't think carbon balls are suitable for lightning protection. Think of
the voltage drop that would appear across each ball during a direct hit. I
think they would vaporize.
At
www.rossengineeringcorp.com/toroids_spheres_coronary_nuts.htm
Ross recommends carbon for lightning.
Dave WX7G
On Jul 27, 2012 9:33 AM, Mike Waters mikew...@gmail.com wrote:
I don't think carbon balls are suitable for lightning protection. Think of
the voltage drop that would appear across
- Original Message -
From: Mike Waters mikew...@gmail.com
To: topband topband@contesting.com
Sent: Friday, July 27, 2012 11:33 AM
Subject: Re: Topband: Spark gaps
I don't think carbon balls are suitable for lightning protection.
I agree. The last thing we want is high surface
www.rossengineeringcorp.com/toroids_spheres_corona_nuts.htm
On Jul 27, 2012 9:43 AM, DAVID CUTHBERT telegraph...@gmail.com wrote:
www.rossengineeringcorp.com/toroids_spheres_coronary_nuts.htm
Ross recommends carbon for lightning.
Dave WX7G
On Jul 27, 2012 9:33 AM, Mike Waters
Man, I don't know, Dave. How long have they been selling those carbon balls
for that purpose?
I don't have the figures in front of me, but carbon has a significant
amount of resistance. (Maybe that's the secret: the current gets limited as
a result. :-)
It would be interesting to calculate the
Man, I don't know, Dave. How long have they been selling those carbon
balls
for that purpose?
I've never seen a carbon ball in a lightning gap application. I'd have to
see a few after being in action a long time before trusting them.
Broadcast stations use hard metallic balls, as do
Mike, here it is.
The resistivity of amorphous carbon is 35 u ohm meters
(That's a 1 meter cube)
A 1 cube has a resistivity of 1.4 m ohms, a one inch sphere about 3 m ohms.
100 kA for 20 us dumps 600 J into it.
The density of carbon is 2.3 g/cm cubed
The 1 inch sphere has a mass of 20 grams
I do make (all too frequent) mistakes so check away. Carbon is 2000 times
more resistive than copper. Being more resistive the carbon skin depth at
lightning frequencies is much deeper than copper or steel (note the steel
is magnetically saturated).
Dave
On Jul 27, 2012 3:26 PM, Mike Waters
Sent: Friday, July 27, 2012 10:58 AM
To: topband
Subject: Re: Topband: Spark gaps
An air gap using one to two inch diameter balls with only a one or two
millimeter gap provides a nearly uniform field resulting in the fastest
breakdown at repeatable and fairly breakdown voltages but capable
it for 160M.
73,
N2TK, Tony
-Original Message-
From: topband-boun...@contesting.com [mailto:
topband-boun...@contesting.com]
On Behalf Of donov...@starpower.net
Sent: Friday, July 27, 2012 10:58 AM
To: topband
Subject: Re: Topband: Spark gaps
An air gap using one to two inch
Take 2 rods and grind a point on each rod. Point the points toward each other.
There is your spark gap.
You can do the dame thing with copper flat stock used on building grounds in
electrical valts.
Stay on course, fight a good fight, and keep the faith. Jim K9TF/WA9YSD
24 matches
Mail list logo
