Quoted:
If a EMP goes off will my truck start? I have goggled it could not really find anything. |
ah, yes, ar15.com membership and the ability to search...
EMP and vehicles --> ar15.com/forums/topic.html?b=1&f=123&t=567246
Yet another EMP Question --> ar15.com/forums/topic.html?b=1&f=123&t=561953
and to repeat this...
i've been thinking about how to answer this question and others like it ("will X survive a NEMP?") for the past few days. i finally concluded that it might be a useful exercise to turn the situation into a physical, palpable one -- where you can see/feel the situation under discussion.
imagine you are financially very well-off, retired in style from the money you made by shorting Enron shares at their peak. you are currently on a large ocean-going sailboat somewhere in the pacific, stretched out in a hammock in your bathing suit drinking sumptuous red wine out of a hefty glass. several brunette models from the Dutch Institute of Modeling are sunbathing on the foredeck, and a few blond beauties from Norway are playing drunk patty-cakes on the aft deck. life is good.
about 1000 miles away, a meteorite the size of a house traveling over 25,000mph slams into the pacific ocean. like the proverbial stone thrown into a pond, large waves radiate outward from the point of impact. an immense first wave and smaller subsequent waves approach your far away boat.
up to now folks have asked EMP-related questions which can be compared to "will a meteorite hitting the ocean spill the wine in my glass?"
there are a million variables which affect the answer... the depth of the water at point of impact, the approach angle of the meteorite, the density of the meteorite, the decomposition of the meteorite upon impact, the makeup of the bottom of the ocean at point of impact, the varying depth of water as the wave progresses towards your boat, the prevailing wind, the shape of the wave when it arrives at the boat, the size of your boat, the orientation of the boat with respect to the wave, the center of gravity of the boat, the mass of the boat, the boat's current heel, the natural frequency of you in your hammock, the size and shape of your wine glass, the viscosity of the wine, your reaction time and reaction to the wave, and so on and so forth.
put into nice, easy, phsyical terms, the above may help folks understand that there is no single answer to "will my Aimpoint fail?" or "will my ham radio fail" due to an EMP -- the same way we can't answer the question regarding the red wine above. there is also no way to create a protection scheme where the wine will NEVER spill (for example, if the boat itself overturns you will certainly lose the wine). moreover, there are condtions which would appear to be safe but in reality will cause loss of the red wine. a small seemingly "safe" wave with the right peak-to-trough distance may excite the dynamic system that is made up of you, the hammock, and the boat. your hammock will overturn despite the fact that the wave, from strictly an amplitude (height) perspective, seemed "safe".
to continue the comparison with NEMP, it is therefore not enough to say that an RF field of "less than 200 V/m" will not cause an Aimpoint to fail. again, there are simply too many variables to conclude this. a field of 100V/m at a given frequency (or more appropriately, risetime) may be far more destructive than a 500V/m field at other frequencies.
which leads me to this, as others who have BTDT (like CWO) will agree: there is a little black magic to go along with science in anything to do with this area. approaches to protection you think will work turn out not to, and vice versa. and knowing what will work is a matter of many years of experience and careful testing methods. even after the reports are written you know that given the right cicrcumstances, failures can still be induced. most any manufacturer who declares, "our product is EMP-proof" can be quickly found to be unknowing in this discipline. |
ar-jedi
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