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UK In Danger From Electromagnetic Bomb, Says Defense Secretary
judgecorp writes "Britain must build defenses against an EMP bomb, the UK Secretary of Defense Phillip Hammond told a conference today. Electromagnetic Pulse devices mimic the result of a solar flare or a nuclear explosion in the atmosphere, creating a storm of electromagnetic radiation, which can break mobile networks and satellite systems. Any preparation for solar storms must also consider the possibility of deliberate electromagnetic events, warns Hammond."
Proper surge protection, spark gaps, low pass filters, etc provide a high degree of protection. Narrow band antennas of a grounded design such as a yagi, will recieve power within it's passband.
Unshielded electronics such as your clock radio are hard to protect. Shielded equipment with power filtering, metal cases, over voltage protection, etc are relatively safe. Your desk top computer has an antenna wire attached to the keyboard and mouse, so these are vunerable. A traditional RFI metal case tower PC with all external cables removed would make a nice spare that can be quickly deployed after an attack.
A single point ground at the utility power and telcom entry into a building provides high levels of protection against the lower frequency components of an EMP as MOV, Spark Gap, and other protection is fast enough to ground it. A noise filter for the house power will block the higher frequencies so the over voltage devices can protect the load.
http://www.ese.upenn.edu/detkin/instruments/misctutorials/Ground/grd.html
Proper grounding, noise filtering, shielding, and overvoltage protection will provide a high degree of protection to EMP.
The truth shall set you free!
"With EMP bomb, unlike a nuke, you don't waste energy to generate EMR in all the spectrum, with all the unneeded parts like visible light, IR and UV, and heat up surroundings to rather uncomfortable temperatures." - technically true, but somewhat misleading.
Around 0.1% of energy goes into EMP.
For a ten kiloton device, this is still the equivalent of 10 tons of explosive - in EMP.
But - a flux-compression-generator converts about a third of the energy into electricity, and then you get about half from the transmitter, if lucky.
So, to get the equivalent EMP to a 10 kiloton nuclear device, you need of the order of 60 tons of explosives alone.
The generator is likely to double that, and the transmission antenna and magnetrons (which have to be physically large so they don't just arc across) double it again.
So, of the order of 250 tons.
This is 'problematic' to get to a high altitude, where it needs to be, to have more than a local effect.
I note 10 25 ton truck bombs are going to be able to wreck large portions of most financial districts, and be considerably cheaper.
'terrorist' EMP weapons with more than a local (building or three) scale are fantasy.