I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

Kurt Stocklmeir
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Kurt Stocklmeir wrote:
I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

Kurt Stocklmeir
--
--- Posted from http://lu7abf.org.ar/news

--- news://freenews.netfront.net/ - complaints: ---

Very little FM, but as the EMF generated by lightning ranges from near
DC to gamma rays, you likely need to be a bit more specific.

There are these for free:

https://helda.helsinki.fi/bitstream/...7/electrom.pdf

http://www.dtic.mil/dtic/tr/fulltext/u2/a234306.pdf

http://www.lightning.ece.ufl.edu/PDF/01396360.pdf

There are also papers that cost to get if you are interested.


--
Jim Pennino

In article ,
Kurt Stocklmeir wrote:

I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

I think you'll find that your question doesn't "map well" onto how
lightning works.

Saying "AM radio waves" or "FM radio waves" implies that there is a
carrier wave, which is being either amplitude-modulated or
frequency-modulated.

Neither of these is the case for lightning strikes. Lightning
consists of strong, irregular pulses of current with rapid rise
times. Each pulse generates a broadband burst of electromagnetic
energy, with energy content distributed widely across a whole range of
frequencies.

The figure I'm seeing is that a single lightning strike typically
releases about 5 billion joules of energy (5 billion watt-seconds).
Most of this is released in a very short period of time (under a
millisecond).

According to http://www.lightningsafety.com/nlsi_info/thunder2.html
about 90% of the lighting's energy is released as heat, less than 1%
is released as sound, and the rest (call it 10%) is released as
light (and, I presume, other frequencies of electromagnetic energy).
There's a very strong electromagnetic pulse near the lighting stroke
and the earth impact point, due to the high current flow.

In the "radio" frequencies per se (e.g. from a few hundred kHz to a
few hundred MHz) it's probably a fraction of a percent of the total
lightning strike energy... mostly in sharp bursts at the beginning
(and perhaps end) of each individual sub-stroke.

wrote:

Kurt Stocklmeir wrote:
I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

Kurt Stocklmeir
--
--- Posted from http://lu7abf.org.ar/news

--- news://freenews.netfront.net/ - complaints: ---

Very little FM, but as the EMF generated by lightning ranges from near
DC to gamma rays, you likely need to be a bit more specific.

There are these for free:

https://helda.helsinki.fi/bitstream/...7/electrom.pdf

http://www.dtic.mil/dtic/tr/fulltext/u2/a234306.pdf

http://www.lightning.ece.ufl.edu/PDF/01396360.pdf

There are also papers that cost to get if you are interested.

I expect that when the OP says AM and FM he means medium wave and VHF
broadcast frequencies. The loud impulse noises one hears on a radio
during storms tend to confirm that quite a lot of EM energy is put out
at all frequencies, as you say. Even FM radios usually fail to reject
it completely, but then they may be receiving it in their audio
circuits.

--
Roger Hayter

On 2/20/2015 5:26 PM, Dave Platt wrote:
In article ,
Kurt Stocklmeir wrote:

I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

I think you'll find that your question doesn't "map well" onto how
lightning works.

Saying "AM radio waves" or "FM radio waves" implies that there is a
carrier wave, which is being either amplitude-modulated or
frequency-modulated.

Neither of these is the case for lightning strikes. Lightning
consists of strong, irregular pulses of current with rapid rise
times. Each pulse generates a broadband burst of electromagnetic
energy, with energy content distributed widely across a whole range of
frequencies.

The figure I'm seeing is that a single lightning strike typically
releases about 5 billion joules of energy (5 billion watt-seconds).
Most of this is released in a very short period of time (under a
millisecond).

According to http://www.lightningsafety.com/nlsi_info/thunder2.html
about 90% of the lighting's energy is released as heat, less than 1%
is released as sound, and the rest (call it 10%) is released as
light (and, I presume, other frequencies of electromagnetic energy).
There's a very strong electromagnetic pulse near the lighting stroke
and the earth impact point, due to the high current flow.

In the "radio" frequencies per se (e.g. from a few hundred kHz to a
few hundred MHz) it's probably a fraction of a percent of the total
lightning strike energy... mostly in sharp bursts at the beginning
(and perhaps end) of each individual sub-stroke.


That website is a little bit misleading, probably in the interest of not
confusing the non-technical readers. After all, heat is also
electromagnetic energy

But effectively, lightning is a very broad band pulse - running from a
few kHz (or lower) well into the high electromagnetic range. Strong
strokes are even known to generate gamma rays (and according to recent
theories, antimatter).

But you're correct - the total amount of energy in the RF range (say
3kHz to 30GHz) is pretty small.

As a sidelight - I remember back in the 60's a lightning detector
project. Basically it was a pair of hula hoops; slit each hoop and wrap
them with several turns of small-gauge wire. These fed a pair of
balanced amplifiers which then fed the X and Y axes of a oscilloscope.
A vertical antenna fed an unbalanced amplifier which then fed the Z axis
of the scope to brighten or darken the trace, depending on the phase
(and therefore the direction) of the incoming signal. Properly
calibrated, the result would be a line from the center of the scope in
the direction of the lightning stroke with the length proportional to
the strength (and roughly inversely proportional to the distance) of the
bold. It pretty cheap to build (I was a high schools student, after
all) but a lot of fun to play with.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

Dave Platt wrote:
In article ,
Kurt Stocklmeir wrote:

I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

I think you'll find that your question doesn't "map well" onto how
lightning works.

Saying "AM radio waves" or "FM radio waves" implies that there is a
carrier wave, which is being either amplitude-modulated or
frequency-modulated.

"AM radio waves" and "FM radio waves" are laymen's terms for
"waves around 1 MHz" and "waves around 100 MHz" respectively.

On 2/20/2015 4:36 PM, Kurt Stocklmeir wrote:
I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

The answer to the question "has anyone tried to find out" is yes, there
have been a couple of genuine properly conducted studies (Several in
fact) into how much power is present in a lightening bolt.. They did
not, far as I know, break it down into AM or FM (RF power is RF power,
how you modulate it is up to you) but they have measured it, Many times.

now, the implied question: How much power in a lightening bolt? I once,
long ago, knew the answer, Since I have read a couple of those studies,
or read of them,,, and I have also, long ago, forgotten the answer.



--
Home, is where I park it.

---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com

On 2/20/2015 5:19 PM, wrote:
Kurt Stocklmeir wrote:
I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

Kurt Stocklmeir
--
--- Posted from http://lu7abf.org.ar/news

--- news://freenews.netfront.net/ - complaints: ---

Very little FM, but as the EMF generated by lightning ranges from near
DC to gamma rays, you likely need to be a bit more specific.

Gamma rays...? Really?

--

Rick

On 2/24/2015 6:07 PM, rickman wrote:
On 2/20/2015 5:19 PM, wrote:
Kurt Stocklmeir wrote:
I would like to know how much am and fm radio waves are made by
lightning

has any person tried this - when lightning is around use their
radio to find how many watts of am and fm radio waves are made by
lighning

thank you for any answers

Kurt Stocklmeir
--
--- Posted from http://lu7abf.org.ar/news

--- news://freenews.netfront.net/ - complaints: ---

Very little FM, but as the EMF generated by lightning ranges from near
DC to gamma rays, you likely need to be a bit more specific.

Gamma rays...? Really?

I guess I should have read first. They speculate that electrons
traveling at near light speeds encounter nuclei and release their energy
as gamma ray photons. Very interesting. Seems this was discovered
relatively recently (~20 years ago).

Even so, the gamma rays are not a direct part of the radiation of the
lightning bolt, but rather are a result of the large EM field and are
relatively uncommon compared to lightning in general.

--

Rick

In article , rickman wrote:

Very little FM, but as the EMF generated by lightning ranges from near
DC to gamma rays, you likely need to be a bit more specific.

Gamma rays...? Really?

Yup. First discovered over 20 years ago.

http://en.wikipedia.org/wiki/Terrest...amma-ray_flash

I've seen more recent reports that suggest that the gamma-ray (and, I
think, X-ray) flux near a lighting stroke can be quite
strong... possibly enough to pose a health hazard to those nearby. It
was suggested that this could be another good reason for commercial
airplanes to avoid flying near thunderstorm cells. Although a
lightning stroke on an airplane does not generally present a shock
hazard to the passengers and crew (the metal body makes a good Faraday
cage) there might actually be enough gamma/X-radiation from the stroke
to give people onboard a hazardous dose.