Afghan Bridge Update and Sad News

On Sun, 18 Nov 2007 02:59:24 -0800 (PST), snipped-for-privacy@yahoo.com wrote:


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), snipped-for-privacy@yahoo.com wrote:

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.

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."

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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Bill sez:
"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"
But be very careful when carrying the microwave oven with the long extension cord. The extension cord may drag over and detonate one of the devices or you may step on one. Advice not up to Bill Nobles usu. standards.
Bob Swinney
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Don sez:
"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."
Yes - very unlikely indeed. At 400 mHz at a distance of 2 feet it would take 200 Watts of power to couple 2 watts into the device; and this assumes no shielding of any kind in the 2 foot path. In other words 200 watts of RF will be attenuated by free space loss down to 2 watts at a distance of 2 feet.
This based on the free space loss formula: FSL = 36.6 + 20 Log D (in miles) + 20 Log F (in mHz)
Bob Swinney
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Robert Swinney wrote:

Does the power absorbed by the load increase by much when one uses a ~30 db gain parabolic antenna instead of that dipole?
Would'nt the ERP off the end of that feedhorn then be in the vicinity of say 120 KW? http://www.powerantenna.ca/calc_ERP.html
--Winston
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