Can you honestly say that an electromagnetic pulse cannot be generated by
anything but an atomic explosion?


"Richard Clark" wrote in message
...
On Sat, 14 Aug 2004 18:29:56 GMT, "Ralph Mowery"
wrote:


"CW" no adddress@spam free.com wrote in message
...
What part of "electromagnetic pulse" refers to nuclear blast?


For many that is what is thought of. Just as when someone mentions
dropping
THE bomb. It is thought of as nuclear.
An air burst is suspose to cause the EMP that will fry most electronics.


For All,

reference "The Electromagnetic Bomb (E-Bomb)":
http://www.airpower.maxwell.af.mil/a...pp/apjemp.html

"The ElectroMagnetic Pulse (EMP) effect [1] was first observed
during the early testing of high altitude airburst nuclear weapons
[GLASSTONE64]. The effect is characterised by the production of a
very short (hundreds of nanoseconds) but intense electromagnetic
pulse, which propagates away from its source with ever diminishing
intensity, governed by the theory of electromagnetism.
...
"Even if the pulse is not powerful enough to produce thermal
damage, the power supply in the equipment will readily supply
enough energy to complete the destructive process. Wounded devices
may still function, but their reliability will be seriously
impaired. Shielding electronics by equipment chassis provides only
limited protection, as any cables running in and out of the
equipment will behave very much like antennae, in effect guiding
the high voltage transients into the equipment."

Note, the EMP of the Flux Compression Generator, an example of a
tactical E-Bomb, is VASTLY richer in current unlike a lightning
strike:
"The FCG is a device capable of producing electrical energies of
tens of MegaJoules in tens to hundreds of microseconds of time, in
a relatively compact package. With peak power levels of the order
of TeraWatts to tens of TeraWatts, FCGs may be used directly, or
as one shot pulse power supplies for microwave tubes. To place
this in perspective, the current produced by a large FCG is
between ten to a thousand times greater than that produced by a
typical lightning stroke [WHITE78]."

However, these intense currents are not widely suitable for mission
purposes for the same reasons of the Lightning's current pulse:
"Whilst FCGs are potent technology base for the generation of
large electrical power pulses, the output of the FCG is by its
basic physics constrained to the frequency band below 1 MHz. Many
target sets will be difficult to attack even with very high power
levels at such frequencies..."

Details abound in this paper, which I will leave to the student to
absorb. Of particular note are the statements about coupling
efficiency (unpredictable) and range (hundreds of meters).

73's
Richard Clark, KB7QHC

"CW" no adddress@spam free.com schreef in bericht
...
Can you honestly say that an electromagnetic pulse cannot be generated by
anything but an atomic explosion?

Lightning?

gr, hwh

On Sun, 15 Aug 2004 11:53:19 -0700, "CW" no adddress@spam free.com
wrote:

Can you honestly say that an electromagnetic pulse cannot be generated by
anything but an atomic explosion?


Hi OM,

I can honestly say that an EMP can be generated by walking across a
wool carpet and touching a faucet handle. I could describe striking a
match as a conflagration or dropping a glass as a shattering
experience.

The term EMP is derived from a truly BIG event with truly BIG
consequences. Trying to elevate smaller examples and saying the
outcome is equal, is not honest at all. The nuclear EMP is orders of
magnitude higher in frequency and currents BOTH compared to lightning.
Saying that the EMP of lightning will cause the same disabilities has
been thoroughly discounted by sheer lack of evidence. We've had both
electronic gear and lightning for a long time, and no one noticed EMP
until they dropped The Bomb. Now, EMP is like sighting Elvis.

I have vaporized a screwdriver with far, far less current than
lightning has found its way unscathed through smaller radius wire.
The recitation of astounding numbers does not make an argument. Even
the Air Force's E-Bombs show they can eclipse lighting's current, to
no greater destruction (which was not particularly effective in the
first place).

73's
Richard Clark, KB7QHC

CW wrote:
Can you honestly say that an electromagnetic pulse cannot be generated by
anything but an atomic explosion?

An electromagnetic pulse can be generated by a time domain
reflectometer.



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SpamHog wrote:
I. I am building a T2FD, for receiving and *maximum* 10W RF out.

10W out of the antenna or 10W out of the transmitter? With a
T2FD, there is a very large difference on certain frequencies.



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hwh wrote:

"CW" no adddress@spam free.com schreef in bericht
...
Can you honestly say that an electromagnetic pulse cannot be generated by
anything but an atomic explosion?

Lightning?

gr, hwh


Google "EMP Test"

Dave

Cecil,

10W out of the antenna or 10W out of the transmitter? With a
T2FD, there is a very large difference on certain frequencies.

Out of the TX. I know that the lower you go, the warmer the pigeon
sitting on the resistor will get.

I tested the small neons I have. I basically found two types, one that
clips at 60V, the other at 110V. I made a classic 4:1 balun and
soldered one 60V between each balanced arm and common. I know it's
like wearing suspenders and belt, but I don't think they will hurt at
under 10W.


Also, in view of what I read, I understand Richard's claim that a T2FD
will snuff out much of the energy anyway:

- if the spectrum of the AC induced by a near hit is mostly in the LF
to MF range, the resistor will indeed take most of the heat, just as
if the power were coming from the coax

- moreover, as I sized the windings for 4MHz and up, the balun itself
will short to ground much of the leftover energy it does receive from
a near hit.

Why, the terms "electromagnetic" and "pulse" should be common knowledge to
anyone that has any interest in this group.

"Dave Holford" wrote in message
Google "EMP Test"

Dave

Richard Clark wrote in message news:

Returning to the issue of lightning, I would suggest you mine the
archives of rec.radio.amateur.antenna for Richard Harrison, KB5WZI


More silly musings:

I read, among other things, that the advice to introduce a coax shield
RF choke as lightning protection has been dropped, mostly on the
grounds that a choke is an EMP pickup.
Hmmmm... That applies to a helical wound inductor, not an
isotropically near-deaf winding like a toroid.
In turn, a single-layer toroid winding would offer a flashover point
between the hot and cold ends of the winding.

OTOH if the inductor is made
- with a couple of windings on straight drainpipe
- electrically in series
- axes parallel
- oppositely oriented
- spaced enough to reduce mutual inductance (say, one yard or more),
what you get is high insulation, no flashover point, limited
pulse pickup (as long as the distance between the windings is that
the distance between them and the putative pulse source).

Another trick would be to make it a single shielded winding.
(Insert warning about inductively shorted winding here -- )

Yet another would be the SPL, the satanist pentagonal layout. It's
like a toroid, cept the winding is split in 5 parts, each in the
middle of the 3-foot side of a pentagon. The two ends are kept well
apart, of course. A weatherproof chandelier is to be lit in the
middle as storms approach.

Sounds like fun.

If I find the inspiration I'll put in a phase canceling split-winding
choke.

On 20 Aug 2004 00:33:58 -0700, (SpamHog) wrote:

More silly musings:

Hi OM,

I'll tell ya what.... Instead of musing, or re-inventing the wheel,
you already have examples from others who went before you with this
identical risk and obviously you think they solved it (or at least
they dress like those who could).

Climb to the top of the building (you HAVE done this, haven't you?)
and LOOK at those antennas and feed lines already there. Do they have
this protection you fantasize about? Do they treat anything as
ground? Do their lines tie to it?

Is there any evidence of lightning strikes? After all, according to
reports here, the flicker of 100000A will melt unobtainium - is that
tower sagging from recent bolts blasted against it? Are there any
explosion marks and charring along those lines? Do you notice any
heat stress fractures where the tower is mounted?

Look over the side, or visit the sidewalk below. Are their any
puddles of slag or molten metal? Or is there any evidence of a fine
metal particulate mist deposited along side the building (it will look
glittery like Disco Makeup for a drag queen)?

No? Do you think they ignored the problem? (What are the chances
anyway?) Do you think you will attract a problem they have never
experienced? Ask yourself, what makes your antenna so much more
attractive when the Eiffel Tower looms over it.

Well, of course there are the products of that near-nuclear EMP. Look
around and see how well the occupants of the building survived this
terrible act. Is there a high tenant turnover every season of
lightning activity? Have you noticed a lot of hearses in the parking
lot on occasion (which begs the question, why weren't you fitted into
a box too)? When you took your trash out, were there piles of
smoldering phones, computers, TVs, clock radios and Internet toasters
filling the bins after a rain? The haphazard, zig-zag AC wiring you
describe should guarantee these results to some degree - at least
enough to reveal any one of these characteristics of catastrophic
results.

Finally, and to answer the question why your antenna, and not the
goliath above it; building those pentangle chokes may if fact incur a
vengeful bolt delivered directly to you. Who knows, in this modern
age that religious metaphor may be embellished to a nuclear cruise
missile to fulfill the prophecy of EMP. (Ah! Images of Monty
Python's Holy Hand Grenade come to mind.)

Let us know how it turns out. ;-)

73's
Richard Clark, KB7QHC