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Old October 5th 09, 10:53 PM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

A friend of mine cited a claim in a brand new book, "The Lost Symbol" by Dan
Brown. So said, in it is a claim of a new weapon of choice that is installed
in some USA military helicopters which is cable of aiming an actual EMP pulse
at a target below that destroys computer and electronic equipment of focus to
the pulse! Same as a 'normal' 30Megavolt/Meter EMP pulse from a nuclear
device, or even a huge Solar Burst. As told me they used it recently to
silence an Email production site they had to quickly do so that they couldn't
do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the USA in
the mid-1800's about the time of the Golden Spike. So history says, it
completely took out most of all the at-the-time telegraph systems which all had
to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how it would
be possible to create and focus an EMP pulse that could be used as described in
an airborne delivery machine? What might the antenna be like?

Just curious.

W5WQN

--


-- Sleep well; OS2's still awake!

Mike Luther
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Old October 5th 09, 11:43 PM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?


"Mike Luther" wrote in message
...
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter EMP
pulse from a nuclear device, or even a huge Solar Burst. As told me they
used it recently to silence an Email production site they had to quickly do
so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the USA
in the mid-1800's about the time of the Golden Spike. So history says, it
completely took out most of all the at-the-time telegraph systems which
all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how it
would be possible to create and focus an EMP pulse that could be used as
described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN

--


-- Sleep well; OS2's still awake!

Mike Luther




The antenna would need to be paraphysical to achieve the kind of directivity
gain needed to create such a field strength whilst capable of being mounted
on a helicopter. Are you sure you're not out by several factors of ten in
respect of the field strength?

Chris

PS: ... however, this is the right place to meet pedlars of paraphysical
antennas!


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Old October 5th 09, 11:53 PM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

On Mon, 05 Oct 2009 21:53:50 +0000, Mike Luther
wrote:

At any rate, can anyone here conjecture, or better still, teach me how it would
be possible to create and focus an EMP pulse that could be used as described in
an airborne delivery machine? What might the antenna be like?


It's called RADAR.

73's
Richard Clark, KB7QHC
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Old October 6th 09, 01:29 AM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

Mike Luther wrote:
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter
EMP pulse from a nuclear device, or even a huge Solar Burst. As told me
they used it recently to silence an Email production site they had to
quickly do so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the
USA in the mid-1800's about the time of the Golden Spike. So history
says, it completely took out most of all the at-the-time telegraph
systems which all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how
it would be possible to create and focus an EMP pulse that could be used
as described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN


Gyrotron, driven by a Flux Compression Generator.

basically a very high power microwave transmitting tube at a high enough
frequency where a moderate sized antenna gives a narrow beamwidth (e.g.
at 10GHz, a 2 meter antenna has about a 1 degree beamwidth.. 100GHz with
a 20 cm antenna does the same.) , with a HV pulse generator that uses
the mechanical energy from an explosion to generate the HV high current
pulse to run the tube.


Now.. 30 MV/m at a distance of say, 200 meters..

Assuming you're in the far field, so E/H = 377 ohms.. H = 30MV/m/ 377 =
0.08 MA/m. 30MV/m * 80kA/m = 2.4E12 W/m^2... that's a pretty high power
density (far higher than you'd need, in this application by the way...
a few tens of kW/square meter would probably do)

But, continuing on.. let's say you've got a 0.57 degree beamwidth.
That's about 0.01 radian, so at 200m, the "spot" is 2 meters in
diameter, or, call it 3-4 square meters.

That means the source has to put out a peak power of about 1E13 Watts..
Say the pulse is a microsecond long.. that's 1E7 joules (10 Megajoules)
which isn't a lot of energy. But a terawatt peak power? That's hard to
believe.

So lets move on.. Average powers of a megawatt are certainly
reasonable.. Let's scale back our field to 30 kV/m (so the power density
is now 2.4E6W/m^2... still 2400 times brighter than the sun)

That's a lot more realistic, and still enough to zap stuff.
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Old October 6th 09, 10:43 AM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?


"Jim Lux" wrote in message
...
Mike Luther wrote:
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter EMP
pulse from a nuclear device, or even a huge Solar Burst. As told me they
used it recently to silence an Email production site they had to quickly
do so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the
USA in the mid-1800's about the time of the Golden Spike. So history
says, it completely took out most of all the at-the-time telegraph
systems which all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how it
would be possible to create and focus an EMP pulse that could be used as
described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN


Gyrotron, driven by a Flux Compression Generator.

basically a very high power microwave transmitting tube at a high enough
frequency where a moderate sized antenna gives a narrow beamwidth (e.g. at
10GHz, a 2 meter antenna has about a 1 degree beamwidth.. 100GHz with a 20
cm antenna does the same.) , with a HV pulse generator that uses the
mechanical energy from an explosion to generate the HV high current pulse
to run the tube.


Now.. 30 MV/m at a distance of say, 200 meters..

Assuming you're in the far field, so E/H = 377 ohms.. H = 30MV/m/ 377 =
0.08 MA/m. 30MV/m * 80kA/m = 2.4E12 W/m^2... that's a pretty high power
density (far higher than you'd need, in this application by the way... a
few tens of kW/square meter would probably do)

But, continuing on.. let's say you've got a 0.57 degree beamwidth. That's
about 0.01 radian, so at 200m, the "spot" is 2 meters in diameter, or,
call it 3-4 square meters.

That means the source has to put out a peak power of about 1E13 Watts..
Say the pulse is a microsecond long.. that's 1E7 joules (10 Megajoules)
which isn't a lot of energy. But a terawatt peak power? That's hard to
believe.

So lets move on.. Average powers of a megawatt are certainly reasonable..
Let's scale back our field to 30 kV/m (so the power density is now
2.4E6W/m^2... still 2400 times brighter than the sun)

That's a lot more realistic, and still enough to zap stuff.



.... but how much damage is a pulse of 10 GHz RF going to do? The
effectiveness of a nuclear EMP much to do with its very broad bandwidth (as
well as its rise time).

Not that I know anything about the subject, Officer.

Chris




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Old October 6th 09, 01:26 PM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

Dan Brown?
plunk

Mike Luther wrote:
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter
EMP pulse from a nuclear device, or even a huge Solar Burst. As told me
they used it recently to silence an Email production site they had to
quickly do so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the
USA in the mid-1800's about the time of the Golden Spike. So history
says, it completely took out most of all the at-the-time telegraph
systems which all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how
it would be possible to create and focus an EMP pulse that could be used
as described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN

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Old October 6th 09, 05:31 PM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

On Tue, 6 Oct 2009 10:43:10 +0100, "christofire"
wrote:

... but how much damage is a pulse of 10 GHz RF going to do?


Stand in front of an unfocussed emitter such as an open microwave oven
for 10 minutes (say, a meter back); that would be about 100,000
pulses; divide your noted effects by the same number and report back.

73's
Richard Clark, KB7QHC
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Old October 7th 09, 12:14 AM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

christofire wrote:
"Jim Lux" wrote in message
...
Mike Luther wrote:
A friend of mine cited a claim in a brand new book, "The Lost Symbol" by
Dan Brown. So said, in it is a claim of a new weapon of choice that is
installed in some USA military helicopters which is cable of aiming an
actual EMP pulse at a target below that destroys computer and electronic
equipment of focus to the pulse! Same as a 'normal' 30Megavolt/Meter EMP
pulse from a nuclear device, or even a huge Solar Burst. As told me they
used it recently to silence an Email production site they had to quickly
do so that they couldn't do any other way, per this book....

Duhh .....

Few people seem to recall the last huge Solar Burst we got here in the
USA in the mid-1800's about the time of the Golden Spike. So history
says, it completely took out most of all the at-the-time telegraph
systems which all had to be rebuilt or replaced.

At any rate, can anyone here conjecture, or better still, teach me how it
would be possible to create and focus an EMP pulse that could be used as
described in an airborne delivery machine? What might the antenna be
like?

Just curious.

W5WQN

Gyrotron, driven by a Flux Compression Generator.

basically a very high power microwave transmitting tube at a high enough
frequency where a moderate sized antenna gives a narrow beamwidth (e.g. at
10GHz, a 2 meter antenna has about a 1 degree beamwidth.. 100GHz with a 20
cm antenna does the same.) , with a HV pulse generator that uses the
mechanical energy from an explosion to generate the HV high current pulse
to run the tube.


Now.. 30 MV/m at a distance of say, 200 meters..



... but how much damage is a pulse of 10 GHz RF going to do? The
effectiveness of a nuclear EMP much to do with its very broad bandwidth (as
well as its rise time).




Actually, I was thinking more like 100GHz, so the beamwidth would be
small for a reasonable sized reflector.

But, you've also identified the key thing when evaluating EMP vulnerability.
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Old October 7th 09, 12:26 AM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?


"Richard Clark" wrote in message
...
On Tue, 6 Oct 2009 10:43:10 +0100, "christofire"
wrote:

... but how much damage is a pulse of 10 GHz RF going to do?


Stand in front of an unfocussed emitter such as an open microwave oven
for 10 minutes (say, a meter back); that would be about 100,000
pulses; divide your noted effects by the same number and report back.

73's
Richard Clark, KB7QHC



If you believe that's the basis of EMP then I won't argue with your opinion.

Chris


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Old October 7th 09, 12:34 AM posted to rec.radio.amateur.antenna
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Default Focused EMP pulse?

Richard Clark wrote:
On Tue, 6 Oct 2009 10:43:10 +0100, "christofire"
wrote:

... but how much damage is a pulse of 10 GHz RF going to do?


Stand in front of an unfocussed emitter such as an open microwave oven
for 10 minutes (say, a meter back); that would be about 100,000
pulses; divide your noted effects by the same number and report back.

73's
Richard Clark, KB7QHC


More like, put your radio in a microwave and turn it on.

60 pulses/second (in the US).. 600W average power. Figure the power
density is probably in the 10 W/cm^2 rough order of magnitude, or
100kW/square meter. Peak to average ratio in a microwave oven is pretty
low (3?), so thermal effects on a lossy medium will be significant.


The 30kV/m (which is achievable as described earlier, a megawatt over
that 2 meter circular area) is around 24 times that. I think it's safe
to say that 30kV/m sorts of fields will fry stuff, in general, pretty
much independent of its resonant properties. Crumpled aluminum foil
sparks pretty well, as does steel wool.


As for personnel exposure..

Yep, you'll get a burn.. probably cook your eyeballs too. Although, at
100GHz, the penetration depth is small..Might just cook your skin off
like a horror movie.

I don't know what the penetration scale depth at 10 GHz is, off hand.
Certainly several cm (I'd expect it to scale as sqrt(1/f), and 2.45 GHz
in a microwave oven clearly penetrates 10 cm at least, or you couldn't
cook a big roast at all evenly)

That's the challenge, of course.. High enough fields to cause
arcs/breakdown to destroy the electronics, but low enough average power
that thermal effects are minimal, so you don't kill or injure the people.


1-10 MW peak powers at pulse lengths of microseconds are pretty standard
radar fare. Fire it at 1pps, and the average power will be down in the
few watts area, so personnel safety isn't as big a problem. There are
lots of cases of folks being exposed to fields of this magnitude
accidentally, and they don't die as a rule.

There is a tale in the FCC enforcement literature about a guy working on
a FM broadcast tower where he noticed sparking and smoke from his
protective garments after the station manager remotely turned the
transmitter on to full power.


On a smaller scale, I've accidentally killed quite a few pieces of
electronics with fast HV pulses. It kind of goes with the territory when
you fool with Marx banks and solid state electronics. Even fairly low
powered Tesla coils will do a number on garage door openers, but I think
that's because the GDOs are kind of cheap designs, with long wires
hanging out of them, and it doesn't take much to kill one. That's
basically discharging a 50pF cap charged to 100-200kV in a few tens of ns.
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