From: mikkelhaaheim@gmail.com   
      
   Le mercredi 16 novembre 2016 23:40:23 UTC+1, nu...@bid.nes a écrit :   
      
   >   Quick answer- with magnetometers, which are ridiculously sensitive these   
   days and with radio receivers, for which ditto. They will only get better as   
   time passes.   
      
   Yes. Magnetometres are sensitive... but they still have to be within the   
   magnetic field. But more about that shortly when we get to range.   
      
   I have been a bit tired lately. I was locked into the context of the magnetic   
   pulse, and was overlooking the RF pulse component. That would be MUCH easier   
   to detect at distance. But more about that, too.   
      
   >    
   >   Do you know what an Non-Nuclear Electromagnetic Pulse Weapon is? It   
   generates an intense magnetic field in a very small volume that then radiates   
   away from the point of generation, inducing destructive electric current in   
   conductors hundreds of miles    
   away, and easily detectable non-destructive current in magnetometers thousands   
   of miles away. The same effect results from nuclear explosions:   
      
   This is actually the point I was trying to get at. We haven't been talking   
   about thousands of miles distance. We have been discussing tens of MILLIONS of   
   miles of distance.   
   Magnetometeres are good... but at such ranges, all they will be picking up are   
   the solar flux.   
      
      
   >    
   >   Basically, your launcher is an enormous NNEMP radiating terajoules per   
   shot, much greater than current nuclear weapons do.   
   >    
   >   The field doesn't expand out from the muzzle during firing and then   
   contract back into the muzzle like a balloon being inflated and then deflated-   
   it radiates out to infinity. Magnetometers are cheap and will be in use by all   
   participants in any    
   conflict for other reasons.   
   >    
   >   Worse, the shorter the pulse, the more of the EM spectrum its energy is   
   spread over, meaning it will appear on every radio receiver for millions of   
   miles around as a burst of static with the exact same "suspicious" spectrum   
   for each shot. Correlating    
   those bursts from multiple magnetometers and radio receivers will give   
   excellent detection data.   
      
      
   You appear to be making some assumptions that are not necessarily valid. I   
   don't know if you are taking into account that the mass from a single attack   
   will be in the form of a volley/salvo from a battery of launchers at multiple   
   locations. However, even    
   if we were discussing just the output from a single launcher, with a single   
   heavy load (say 1 tonne, max), this does NOT imply a single superowered, short   
   duration pulse. First, it is far more likely that the launch will be in the   
   form of a series of    
   weaker pulses (yes, this would make it easier to determine the vector of fire,   
   IF detected by something with sufficient resolution, but it also makes it much   
   harder to detect). Second, those pulses are likely to be longer duration,   
   applied over a longer    
   distance.   
      
      
   >   Er, no, it's not like a laser- the pulse will radiate from the muzzle   
   spherically. Reception of the static from many locations (spacecraft and space   
   stations), even using omnidirectional antennas that don't individually give   
   direction information,    
   can be correlated time-wise to yield direction data and signal strength   
   correlation will yield distance data.   
      
   There is already technology that shields against such pulses to various   
   degrees. It might not currently be practical, but one can assume that such   
   tech will continue to improve. Of course, the consequence will be more waste   
   heat, but that essentially    
   just means a better ejection system.   
   But yes... anything that DOES get out will be radiating roughly spherically...   
   which makes it more difficult to determine the direction of fire.   
      
   >   
      
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