Re: Lightning protection

w_tom wrote:
The radio is tuned only to receive a specific frequency. That pulse is composed of many frequencies. 

The pulse is a pulse.

Frequency that
interferes with radio reception is a unique sine wave
frequency
within that pulse. 

You're really hung up on those sine waves for some reason.
Fourier analysis is a mathematical construct (admittedly
a very useful one), but it's a fiction (in the best sense
of the word).  The lightning isn't "created" from sine
waves.

Just one of so many frequencies that
create the pulse. Pulses - like all waveforms - are a
summation of basic sine waves at different frequencies,
amplitudes, and phases. 

So what's the phase of the third sine wave in the series?
What physical phenomenon results in that phase?  Does the
Fourier series you contend results in the single lightning
pulse match it through all time?  Think about what you're
saying.

The radio does not receive a pulse. 

Huh?  Why not?

It receives only parts of a waveform that are specific to its
tuned frequency. Fourier analysis demonstrates the concept. The radio does not receive a pulse so much as it receives one
frequency that was part of that pulse. 

So what magic keeps the other parts of the pulse away from the radio?
Face it, the radio gets the full pulse and processes it into whatever
you hear.


  A chart for the frequency spectrum of lightning is available
in:
http://www.hubersuhner.com/products/hs-p-rf-lp-kb/hs-p-rf-lp-kb-bas/hs-p-rf-lp-kb-bas-fre.htm
.


Did you look at the scale on that chart?  Is that your idea of RF?
Looks more like audio to me.

What does DC arcing create? That was how radios worked. Sparking DC electricity created AC electricity that resulted
in radio waves. Telsa did not transmit DC electricity. To
perform electricity transmissions, DC electricity was
converted to AC. DC arcing is detected how? By measuring AC
components created by that arcing. 


You're arguing with yourself.  I didn't say it was DC (or AC for
that matter -- the DC/AC distinction, as explored recently in
another thread, is not necessarily useful in a discussion such
as this).


  Meanwhile TimPerry repeatedly refers to DC pulses.  That
would be DC analysis.  Lightning pulse is AC electricity.  It
creates electromagnetic waves of same frequencies.  You even
have a chart for that frequency spectrum.  What the chart does
not show is how the energy content quickly tapers to zero as
frequency approaches DC.  That pulse called lightning is
composed of electricity at RF frequencies.


I suspect we're more in agreement than would appear.  But my problem
with your position is twofold:

- your insistence that a pulse in nature is somehow created from lots
of sine waves; maybe it's just the words you use, but I have a
philosophical problem with projecting a mathematical analysis
technique onto nature as more than an analogy

- (not explored here yet, but related) your claim in one of your
posts that a sharp bend in a ground wire would necessarily destroy
its effectiveness in shunting lightning to ground because of effects
on its impedance.  I think you also contend that wrapping a coil
around the wire would cause a similar problem.  I assume you would
then contend that all skyscrapers run their lightning rod ground wires
outside their girder structures, to avoid being encompassed by single
turn coils consisting of metallic girders.

CJT wrote:
w_tom wrote: 
... Lightning is RF electricity.  That RF energy is why
lightning even causes noise on radios. So now you say
all those RF sine waves, demonstrated by Fourier
analysis, really do not exist?

You're demonstrating a basic lack of understanding of
Fourier analysis.  Fourier used the sine function as a
basis function.  That doesn't mean there are sine waves
"in" the pulse.  If he had used some other set of basis
functions, would that "prove" that those other bases were
present in the pulse?

Don't get me wrong -- I'm ok with you saying there's RF
energy in the pulse, but not with your extrapolation to
"RF sine waves."  We're talking about impulses here.
...

The radios are responding to the pulses.  Fourier series are a
useful way to analyze the response.  But the radio is essentially
a filter that alters the signal it sees.  It's not locking on to
some RF sine wave as you seem to think.
...

Huh?  Have you seen those videos of (as I recall) DC arcs in
high voltage transmission tests that are floating around the Web?



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