Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Default Afghan Bridge Update and Sad News

Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken
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Sorry to hear about your loss. There is nothing that comes to mind
that you can do that is easy and works 100%.

i
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--Google on "inductive loop mine detector" for starters and you'll
see a fair number of clever ideas. I'm thinking something like this could
probably be mounted on, or dragged behind an R/C car. Data could be
transmitted to another location. With robotics at their current state it
would be possible to teach a vehicle to sweep an area thoroughly and map the
output.
--Several years ago I lead a team that played around with third world
methods for dealing with mine clearing but since then the available cheap
electronics have greatly increased the possible routes to a solution.

--
"Steamboat Ed" Haas : Whatever happened
Hacking the Trailing Edge! : to Andy Philbrick?
www.nmpproducts.com
---Decks a-wash in a sea of words---
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wrote in message
...
Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken


Boy o boy - what a problem.
They trigger those damn things every way there is a trigger I think.

Cell phones, timers, pressure plates, Achmed with a toggle switch on a long
wire.

Short term solution - Sure wish I knew one. Be interesting to know the
results of projecting a bigass focused EMP field 20 feet in front of the
vehicle.

I think power requirements and cycle time would prohibit running one all
the time, but a crew could have a fire button to hit when passing
suspicious roadside stuff.

Would a Radio controlled small white pickup truck 90 feet in front of an APC
be a useful sensor mount? Inflatable plastic driver behind the wheel.....

Long term solution: Airstrikes on every mullah that preaches JIHAD! against
the great and lesser satan.

Markshere2





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On Sun, 18 Nov 2007 02:59:24 -0800 (PST),
wrote:

Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken


A Toast to the Living
A Drink to the Dead

To Absent Friends!


Gunner, "Sua Sponte"



"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
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I'm reminded of WWII era mine-bashing tank accessories - a drum on long
arms in front of the tank, with many pieces of chain, and the whole drum
spun up to beat the ground and clear a swath. For pressure-plate type
detonators, that should do as well as anything, and should be a known
(if not current) technology. Presumably the drum takes some damage, and
is made to be cheap and easily replaceable.

I suspect there are several problems with reliably getting the damn
things to go off with electricity or magnetics. Presumably, at the silly
end of the scale, you could keep tossing neutron bombs and that ought to
fix them, but with somewhat problematic side effects. As there are going
to many variants, finding something that will manage to set off one is
not likely to manage to set off others, and anything that will have
enough energy to possibly pull it off is probably going to take
something more like a remote-control humvee to have enough power to run
it. Then you have the problem of remotely controlling something that is
actively trying to send out a huge amount of interference (so perhaps
it's controlled via cable, not radio), and the effects of that
interference on communications, etc.

--
Cats, coffee, chocolate...vices to live by


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On Sun, 18 Nov 2007 10:44:23 -0500, Bill Schwab
wrote:

Ken,

Wes wrote:
wrote:

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket".



If you hooked that R/C system up to a humvee with realistic looking
passengers, maybe that would work. AKA Bait.

I suspect that jamming to deny the trigger signal is being used along with
freq sweeping to try to trigger IED a head of convoy.


This sounds like a remotely triggered device. Is that the threat, or
does "pressure plate" mean they trigger on contact?

Have we recovered and disarmed live bombs? It would all depend on the
sophistication and variations in design. My guess is that they are
contact activated and we simply need something other than our soldiers
to push on them. That could take the form of a computer operated and
armored ATV or something to go ahead of you, at least in the open areas.


Thank all of you for your service.


Ditto!

Bill

http://en.wikipedia.org/wiki/Mine_flail
http://en.wikipedia.org/wiki/Hobart%27s_Funnies

Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.


Gunner



"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
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some suggestions:
1. if in a cell phone area, there are cheap commercial cell phone
detectors - use one of them to detect cell phone triggered devices
2. disassemble microwave oven, make horn to direct micorwaves downward, move
the device (fairly slowly) over suspect ground - microwaves are likely (not
guaranteed) to hurt detnoation electronics
3. for things triggered by pressure, you've had a lot of good suggestions
wrote in message
...
Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken




--
Posted via a free Usenet account from http://www.teranews.com

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On Sun, 18 Nov 2007 02:59:24 -0800 (PST),
wrote:

Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken


Unfortunately, the I in IED means "improvised". That means it's
difficult to predict what might detonate one unless it's known that
many or most are "improvised" in the same or similar ways. A purely
mechanical (no electric stuff inside) pressure plate initiator pretty
much only responds to pressure.

The only universal way I know of to detonate something before the
improvisor intended it to happen is by sympathetic detonation -- pop
HE on or very near it.

If it is metal, then it might be either detonated or neutered by
making it hot, which could be done by microwave or RF induction -- but
that'd take far more power than batteries could sustain.

Other ways of countering them also deserve thought: locate them and
avoid them, or if manually fired then locate and destroy the lurker
before he or she can plunk the magic twanger. Gets complicated when
the lurker is a child, don't know if you're seeing any of that or not.
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On Sun, 18 Nov 2007 16:55:32 -0600, Don Foreman
wrote:

Other ways of countering them also deserve thought: locate them and
avoid them, or if manually fired then locate and destroy the lurker
before he or she can plunk the magic twanger. Gets complicated when
the lurker is a child, don't know if you're seeing any of that or not.


Not at all complicated. You just dont have to lead em as much as an
adult.

Gunner



"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
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On Sun, 18 Nov 2007 02:59:24 -0800 (PST),
wrote:

Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.

Thanks,

Ken


The most effective method of getting rid of IEDs is a good strafing
of the road immediately before traveling it. Spray the road and both
sides well with a good shower of lead to detonate anything in range.
Only problem is collateral damage - it liquidates anyone already on
the road, friend or foe.

--
Posted via a free Usenet account from
http://www.teranews.com



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On Sun, 18 Nov 2007 02:59:24 -0800 (PST),
wrote:

Hi Everyone.

Thanks for all the help and advice on the Bridge Project. It's
currently on hold, as the FOB Mayor wants to see if we can score some
honest culvert from an Engineer Unit rather than build some. Works
for me.

On the 12th, we lost two good men and had a third badly injured
courtesy of an IED. If I've figured the time zones right. it would
still have been Memorial Day back home.

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket". I know
that high-tension lines will sometimes induce power in fences running
parallel to the lines. Could this effect be useful against pressure
plate IEDs at a range of a foot or so? If any one has any thoughts on
the subject, no matter how bizarre, I'd love to hear 'em. (Other than
"Just Leave." While effective, it's not in the cards.)


The only really reliable way to trip a pressure plate is to trip the
pressure plate. And they can always rig up a remote bypass and only
flip it on as the truly tempting vehicle approaches.

If you ever watched Mythbusters, you know it's fairly easy to rig up
a car with a garden variety radio control on the gas, steering and
brakes. With a little ingenuity you can do the same to a Humvee, and
a little ingenuity can cover the shifter and other auxiliaries.

Take an un-armored Hummer and rig it to remote control from an
Up-Armored rig a car or two back in line, with dummies in the front
seats to fool the remote trigger folks.

Might even take a second remote control and rig it to the Ma Deuce
on the back - but you need multiple video links (wide angle and aiming
point) to do that right...

Any experimental inductive trigger coils are going to need serious
power to run them. Generator in the back seat will do it.

Might be more effective to just hang a big metal detector coil off
the front of the remote-control lead car - when you drive over the IED
made of old artillery shells it'll scream like a banshee, and you can
let the EOD guys decide if it's a trick or a treat...

Or "borrow" a skid-steer loader from the Seabees, toss a bulletproof
windshield and some armor plate around the operator's position, and
hang the metal detector loop off the bucket. When you get a hit,
retract the loop and dig a hole - the loader bucket should deflect
quite a blast. If it's a dry hole you can fill the divot back in and
compact it before proceeding.

Could use a backhoe tractor, but the little dipper bucket means
armoring the operator position will be far more important.

Too bad you can't call Dig-Alert and have them mark all the mines.
;-) But if there are any working utilities down there, might be a
good thing to know about before you start digging holes in the road.
Digging into a 35KV power feeder cable or a natural gas main would
make a pretty good blast, too.

Way smarter people than me are working on this I'm told. I thought
I'd bring it to the attention of some of the smartest people on the
net. If anyone knows where Fitch Williams hangs out now, he'd be a
good one to ask, too.


Remember that the Field Expedient Modification is a time honored
tradition, the "Hedge-Chopper" tank attachments from WW-II and the
"Flail" style land-mine detonator/clearer being a few famous examples.

You have to be smarter than the enemy. "Your job is not to die for
your country - it's to make the other stupid sonofabitch die for his."

In closing, we can't remember our fallen in the traditional way until
deployments end. If anyone would care to hoist a glass in salute,
I'd be grateful. Godspeed guys.


Thank you for dealing with the baddies over there, rather than
letting them come over here.

-- Bruce --

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I believe that the standard approach is to do all things at once --
watch the road, use cell phone jammers, send sappers forward, and work
with locals for getting tips (could also be a source of trouble).

There is no magic answer as to how to pre-detonate all possible IEDs.
The twisted pair wire is quite immune to any sort of interference.

It is a difficult problem, since ingenious local people are willing to
take considerable risks and they get paid for all soldiers killed and
equipment destroyed.

i
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Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.

Gunner


Yep. That's the word we get from Iraq too. 'Round here, the pressure
plate varients are by far the most common. Construction varies, but
it goes like this...
Take an explosive device, anything from homebrewed explosives to
antique British and Russian A/T mines. Fuse with electric blasting
cap. Bury mine to varying depths. Build a pressure plate from
anything conductive which happens to be in the bomb-maker's reach that
day. Bury shallow. Connect a couple D-Cells via some scavenged wire,
and...wait.

Pressure plates are generally around 18-24 inches long and from 1 to 8
inches wide. Insulators between the plates are anything that won'
conduct too much electicity; from pieces of goat hide to bits of
rubber. Pressure plate assy. is usually water/sand proofed in some
manner. Goat hide, plastic bags, truck innertube, pvc pipe, etc.

Since the pressure plates are generally large, shallow, and not
electrically shielded, I was hoping to target them with an induced
current. Not as easy as I was hoping, I see. If it were simple,
somebody would have figured it out already. Sigh. We'll keep working
the problem.

Thank you all for your help and support!

Ken
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On Mon, 19 Nov 2007 01:33:35 -0800 (PST),
wrote:


Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.

Gunner


Yep. That's the word we get from Iraq too. 'Round here, the pressure
plate varients are by far the most common. Construction varies, but
it goes like this...
Take an explosive device, anything from homebrewed explosives to
antique British and Russian A/T mines. Fuse with electric blasting
cap. Bury mine to varying depths. Build a pressure plate from
anything conductive which happens to be in the bomb-maker's reach that
day. Bury shallow. Connect a couple D-Cells via some scavenged wire,
and...wait.

Pressure plates are generally around 18-24 inches long and from 1 to 8
inches wide. Insulators between the plates are anything that won'
conduct too much electicity; from pieces of goat hide to bits of
rubber. Pressure plate assy. is usually water/sand proofed in some
manner. Goat hide, plastic bags, truck innertube, pvc pipe, etc.

Since the pressure plates are generally large, shallow, and not
electrically shielded, I was hoping to target them with an induced
current. Not as easy as I was hoping, I see. If it were simple,
somebody would have figured it out already. Sigh. We'll keep working
the problem.

Thank you all for your help and support!

Ken



Google on "mine flail". They should work just dandy on a pressure
plate mine.

Should be something a craft shop could put together in a week or so.
Mount it on the front of a bulldozer or similar.

Gunner



"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner
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Gunner Asch wrote:


Google on "mine flail". They should work just dandy on a pressure
plate mine.

Should be something a craft shop could put together in a week or so.
Mount it on the front of a bulldozer or similar.

Gunner



I wonder what a big vibratory soil compactor on a boom would accomplish?

Wes


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Ken,

Since the pressure plates are generally large, shallow, and not
electrically shielded, I was hoping to target them with an induced
current. Not as easy as I was hoping, I see. If it were simple,
somebody would have figured it out already. Sigh. We'll keep working
the problem.


What about a metal detector? Or might that set some of the damn things off?



Thank you all for your help and support!


Again, thank you!

Bill

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On Mon, 19 Nov 2007 01:33:35 -0800 (PST),
wrote:


Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.

Gunner


Yep. That's the word we get from Iraq too. 'Round here, the pressure
plate varients are by far the most common. Construction varies, but
it goes like this...
Take an explosive device, anything from homebrewed explosives to
antique British and Russian A/T mines. Fuse with electric blasting
cap. Bury mine to varying depths. Build a pressure plate from
anything conductive which happens to be in the bomb-maker's reach that
day. Bury shallow. Connect a couple D-Cells via some scavenged wire,
and...wait.

Pressure plates are generally around 18-24 inches long and from 1 to 8
inches wide. Insulators between the plates are anything that won'
conduct too much electicity; from pieces of goat hide to bits of
rubber. Pressure plate assy. is usually water/sand proofed in some
manner. Goat hide, plastic bags, truck innertube, pvc pipe, etc.

Since the pressure plates are generally large, shallow, and not
electrically shielded, I was hoping to target them with an induced
current. Not as easy as I was hoping, I see. If it were simple,
somebody would have figured it out already. Sigh. We'll keep working
the problem.


Metal pressure plates that big and buried shallow would be very easy
for a metal detector to find, and the detector could be desensitized
so it didn't pick up miscellaneous small bits like shrapnel etc.

A metal detector would be small enough and light enough for a small
R/C vehicle to handle, and they draw very little power.
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On Mon, 19 Nov 2007 10:05:24 -0500, Bill Schwab
wrote:

Ken,

Since the pressure plates are generally large, shallow, and not
electrically shielded, I was hoping to target them with an induced
current. Not as easy as I was hoping, I see. If it were simple,
somebody would have figured it out already. Sigh. We'll keep working
the problem.


What about a metal detector? Or might that set some of the damn things off?


Very, very unlikely. There's no closed circuit in the described IED
in which to induce current, and the field of a metal detector is very
weak.

The only way I know of that an EM field can fire a squib is if it's
high enough in frequency (and powerful enough) to induce enough
resonant RF current in the squib leads. Resonance doesn't require a
closed circuit. That'd be at least UHF in frequency, and at least a
couple of watts of power -- and then only if the metal pressure plate
doesn't act as an effective RF shield. Metal detectors typically
operate at kilohertz or low megahertz frequencies.
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On Nov 19, 8:45 pm, Don Foreman wrote:

The only way I know of that an EM field can fire a squib is if it's
high enough in frequency (and powerful enough) to induce enough
resonant RF current in the squib leads. Resonance doesn't require a
closed circuit. That'd be at least UHF in frequency, and at least a
couple of watts of power -- and then only if the metal pressure plate
doesn't act as an effective RF shield. Metal detectors typically
operate at kilohertz or low megahertz frequencies.


My understanding is that the frequency needed depends on the length of
the wires going to the det. And that about 27 MHZ is about right.

Dan



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On Tue, 20 Nov 2007 03:35:56 GMT, Winston
wrote:

wrote:
On Nov 19, 8:45 pm, Don Foreman wrote:


The only way I know of that an EM field can fire a squib is if it's
high enough in frequency (and powerful enough) to induce enough
resonant RF current in the squib leads. Resonance doesn't require a
closed circuit. That'd be at least UHF in frequency, and at least a
couple of watts of power -- and then only if the metal pressure plate
doesn't act as an effective RF shield. Metal detectors typically
operate at kilohertz or low megahertz frequencies.



My understanding is that the frequency needed depends on the length of
the wires going to the det. And that about 27 MHZ is about right.


The idea is to cause inductive heating of the of the squib, yes? There
is no current path via the leads unless you can convince the enemy to
install (say) a capacitor across their series switch.

--Winston


At RF frequencies where the squib leads form a half-wave dipole, no
other current path is necessary. The squib itself would be the
current path and electrical load. 27 MHz would require rather long
squib leads, as might be found in mining, construction or demo setups.
Twisted parts don't count much, but eventually they must separate
enough to engage a switch and battery within an IED.
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Don Foreman wrote:

On Tue, 20 Nov 2007 03:35:56 GMT, Winston
wrote:


wrote:

On Nov 19, 8:45 pm, Don Foreman wrote:



The only way I know of that an EM field can fire a squib is if it's
high enough in frequency (and powerful enough) to induce enough
resonant RF current in the squib leads. Resonance doesn't require a
closed circuit. That'd be at least UHF in frequency, and at least a
couple of watts of power -- and then only if the metal pressure plate
doesn't act as an effective RF shield. Metal detectors typically
operate at kilohertz or low megahertz frequencies.


My understanding is that the frequency needed depends on the length of
the wires going to the det. And that about 27 MHZ is about right.


The idea is to cause inductive heating of the of the squib, yes? There
is no current path via the leads unless you can convince the enemy to
install (say) a capacitor across their series switch.

--Winston



At RF frequencies where the squib leads form a half-wave dipole, no
other current path is necessary. The squib itself would be the
current path and electrical load. 27 MHz would require rather long
squib leads, as might be found in mining, construction or demo setups.
Twisted parts don't count much, but eventually they must separate
enough to engage a switch and battery within an IED.


I understand.
So perhaps an FM microwave power oscillator feeding a downward facing
parabolic antenna? Lots of ERP at all the reasonable frequencies?
Sounds like something worth testing.

--Winston
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On Mon, 19 Nov 2007 08:56:07 -0500, Wes wrote:
Gunner Asch wrote:


Google on "mine flail". They should work just dandy on a pressure
plate mine.

Should be something a craft shop could put together in a week or so.
Mount it on the front of a bulldozer or similar.


I wonder what a big vibratory soil compactor on a boom would accomplish?


You mean besides putting one vibratory soil compactor into low earth
orbit? 8-O

Call NORAD so they can track the trash... On second thought it
probably won't make escape velocity, but "What goes up must come down"
still applies. It's got enough mass to go right through whatever
house or car roof it lands on. Headache!!

That's the nifty thing about a mine flail, the arm is just far
enough away that it should remain attached and mostly undamaged.
You'll lose some of the chains and flail weights in the BOOM!, but
they won't go nearly as far.

-- Bruce --

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How well do the thermal imaging night-vision cameras work in the
field? I built some telescopic lenses for them, about the size of a
gallon paint can with black Germanium front elements, but never heard
anything good or bad about them from the field.


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After a Computer crash and the demise of civilization, it was learned
Gunner Asch wrote on Sun, 18 Nov 2007
11:52:18 -0800 in rec.crafts.metalworking :
On Sun, 18 Nov 2007 10:44:23 -0500, Bill Schwab
wrote:

Ken,

Wes wrote:
wrote:

I have been wondering if there is any way to inductively couple enough
current to prematurely detonate these suckers. Maybe an R/C car with
a rotating coil sort of thing. My knowledge of electricity pretty
much ends with "Don't stick coathangers into the wall socket".


If you hooked that R/C system up to a humvee with realistic looking
passengers, maybe that would work. AKA Bait.

I suspect that jamming to deny the trigger signal is being used along with
freq sweeping to try to trigger IED a head of convoy.


This sounds like a remotely triggered device. Is that the threat, or
does "pressure plate" mean they trigger on contact?

Have we recovered and disarmed live bombs? It would all depend on the
sophistication and variations in design. My guess is that they are
contact activated and we simply need something other than our soldiers
to push on them. That could take the form of a computer operated and
armored ATV or something to go ahead of you, at least in the open areas.


Thank all of you for your service.


Ditto!

Bill

http://en.wikipedia.org/wiki/Mine_flail
http://en.wikipedia.org/wiki/Hobart%27s_Funnies

Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.


And thanks tot he NYT and the rest of "Al Majnoon", the terrs know
about the jamming. So, back to Bell Telephone wire.

tschus
pyotr

"Al Majnoon" is Arabic for "The lunatics", Literally "those possessed of
a djinn (evil spirit)."
--
pyotr filipivich
"Quemadmoeum gladuis neminem occidit, occidentis telum est. "
Lucius Annaeus Seneca, circa 45 AD
(A sword is never a killer, it is a tool in the killer's hands.)
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On Nov 20, 4:21 am, Don Foreman wrote:

At RF frequencies where the squib leads form a half-wave dipole, no
other current path is necessary. The squib itself would be the
current path and electrical load. 27 MHz would require rather long
squib leads, as might be found in mining, construction or demo setups.
Twisted parts don't count much, but eventually they must separate
enough to engage a switch and battery within an IED.


Right. 27 mhz is about 11 meters so for a half wave length dipole
each wire would be about 9 feet. This is what I vaguely remember from
some classes. If you want better information search on " HERO safe
ordnance ".

Dan

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On Tue, 20 Nov 2007 05:39:13 GMT, Winston
wrote:

Don Foreman wrote:

On Tue, 20 Nov 2007 03:35:56 GMT, Winston
wrote:


wrote:

On Nov 19, 8:45 pm, Don Foreman wrote:



The only way I know of that an EM field can fire a squib is if it's
high enough in frequency (and powerful enough) to induce enough
resonant RF current in the squib leads. Resonance doesn't require a
closed circuit. That'd be at least UHF in frequency, and at least a
couple of watts of power -- and then only if the metal pressure plate
doesn't act as an effective RF shield. Metal detectors typically
operate at kilohertz or low megahertz frequencies.


My understanding is that the frequency needed depends on the length of
the wires going to the det. And that about 27 MHZ is about right.

The idea is to cause inductive heating of the of the squib, yes? There
is no current path via the leads unless you can convince the enemy to
install (say) a capacitor across their series switch.

--Winston



At RF frequencies where the squib leads form a half-wave dipole, no
other current path is necessary. The squib itself would be the
current path and electrical load. 27 MHz would require rather long
squib leads, as might be found in mining, construction or demo setups.
Twisted parts don't count much, but eventually they must separate
enough to engage a switch and battery within an IED.


I understand.
So perhaps an FM microwave power oscillator feeding a downward facing
parabolic antenna? Lots of ERP at all the reasonable frequencies?
Sounds like something worth testing.

--Winston


Now it becomes political. Try and find DARPA funding to do any such
research! Hm, I think my pass to the ordnance proving grounds near
St. Francis has expired -- about 30 years ago.
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On Tue, 20 Nov 2007 05:39:13 GMT, Winston
wrote:
Don Foreman wrote:


At RF frequencies where the squib leads form a half-wave dipole, no
other current path is necessary. The squib itself would be the
current path and electrical load. 27 MHz would require rather long
squib leads, as might be found in mining, construction or demo setups.
Twisted parts don't count much, but eventually they must separate
enough to engage a switch and battery within an IED.


And the first (admittedly silly) thing that flashed through my head...

"Breaker One Nine, this here's the Rubber Duck. Hey Pig-Pen, you
got your ears on?..." -=+*(BOOM!)*+=-

I understand.
So perhaps an FM microwave power oscillator feeding a downward facing
parabolic antenna? Lots of ERP at all the reasonable frequencies?
Sounds like something worth testing.

--Winston


The RF is to induce electrical current in the squib leads, and that
current would be the source of the heat to trigger the squib.

And if it doesn't work for that, a 10KW focused microwave beam
certainly will BBQ any roadkill in front of the antenna. ;-)

A properly designed explosive device has the squib leads twisted,
shielded and grounded out, RF shielding and bypass capacitors, and
other things done deliberately to keep stray RF signals out of the
trigger circuit, and all that protection stays in place till the last
possible second. Since premature detonation isn't too healthy for the
bomb builders or the delivery crew.

But IED's are nothing like properly designed explosive devices, so
potentially large doses of RF at the right frequencies could work. At
least till they figure out how we're defeating them...

-- Bruce --

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I would be amazed if simple "wrap it in foil and use twisted wire"
approach did not 100% prevent premature detonation through any kind of
RF generator.

i


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On Tue, 20 Nov 2007 05:35:48 -0800, pyotr filipivich wrote:
Gunner Asch wrote :


Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.


And thanks tot he NYT and the rest of "Al Majnoon", the terrs know
about the jamming. So, back to Bell Telephone wire.

tschus
pyotr

"Al Majnoon" is Arabic for "The lunatics", Literally "those possessed of
a djinn (evil spirit)."


Are you saying that the New York Times, CNN (Clinton News Network)
and other Leftie Loonie US news outlets are deliberately leaking
military secrets on how we're getting a leg up on Al Queda, so the
other side can stop doing those things? As Captain Renault would say
"I'm SHOCKED!"

Not.

Like how Osama Bin Ladin spit stopped using his satellite phone
the second word leaked out we had his number? And we could have
dropped a cruise missile in his lap simply by homing in on it?

"Freedom of the Press" only works with a responsible press. And
responsible means you don't give out operational details that can
affect the outcome while the game is still afoot.

We invented Spread Spectrum frequency hopping scrambling in WW-II,
and many other technological advances that greatly shortened the war.
But word didn't get out about most of them till much later - and that
was entirely on purpose.

-- Bruce --
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Don Foreman wrote:

(...)

Now it becomes political. Try and find DARPA funding to do any such
research! Hm, I think my pass to the ordnance proving grounds near
St. Francis has expired -- about 30 years ago.


I can't help with that problem but I think your 'mine roaster' is an
excellent idea.

--Winston
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"Bruce L. Bergman" wrote in message
news
On Tue, 20 Nov 2007 05:35:48 -0800, pyotr filipivich wrote:
Gunner Asch wrote :


Unfortuatly..most IEDs are command detonated, least thats the word I
get from the sand box.


And thanks tot he NYT and the rest of "Al Majnoon", the terrs know
about the jamming. So, back to Bell Telephone wire.

tschus
pyotr

"Al Majnoon" is Arabic for "The lunatics", Literally "those possessed of
a djinn (evil spirit)."


Are you saying that the New York Times, CNN (Clinton News Network)
and other Leftie Loonie US news outlets are deliberately leaking
military secrets on how we're getting a leg up on Al Queda, so the
other side can stop doing those things? As Captain Renault would say
"I'm SHOCKED!"

Not.

Like how Osama Bin Ladin spit stopped using his satellite phone
the second word leaked out we had his number? And we could have
dropped a cruise missile in his lap simply by homing in on it?

"Freedom of the Press" only works with a responsible press. And
responsible means you don't give out operational details that can
affect the outcome while the game is still afoot.


The news source in question actually was a Rightie Loonie US news outlet:
the Washington Times.

However, even that didn't happen, Bruce. Urban legend:

http://www.truthdig.com/report/item/...hone_20060110/
http://www.slate.com/id/2132975/

etc.

--
Ed Huntress


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On Tue, 20 Nov 2007 15:12:19 -0600, Ignoramus10223
wrote:

I would be amazed if simple "wrap it in foil and use twisted wire"
approach did not 100% prevent premature detonation through any kind of
RF generator.

i


I worked in two-way radio/RF for most of my career. It
really isn't all that easy to shield things from RF. What
looks good to the eye can leak horribly and what you would
swear could never work does...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email
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On 2007-11-21, Leon Fisk wrote:
On Tue, 20 Nov 2007 15:12:19 -0600, Ignoramus10223
wrote:

I would be amazed if simple "wrap it in foil and use twisted wire"
approach did not 100% prevent premature detonation through any kind of
RF generator.

i


I worked in two-way radio/RF for most of my career. It
really isn't all that easy to shield things from RF. What
looks good to the eye can leak horribly and what you would
swear could never work does...


But would RF deliver enough amps to cause detonation?

i
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