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The Pentagon's Ray Gun Can Stall Cars (defenseone.com)
john of sparta quotes Defense One: The Defense Department's Joint Non-Lethal Weapons Program, or JNLWD, is pushing ahead with a new direct energy weapon that uses high-powered microwaves to stop cars in their tracks without damaging the vehicle, its driver, or anyone else.
The jammer works by targeting the car's engine control unit causing it to reboot over and over, stalling the engine. Like an invisible hand, the microwaves hold the car in place. "Anything that has electronics on it, these high-powered microwaves will affect," David Law, who leads JNLWD's technology division, said in March. "As long as the [radio] is on, it holds the vehicle stopped."
It weighs 400 pounds -- it's the size of a large copy machine -- and uses 300 kilowatts of power that's generated by a gasoline-powered turbine.
"To deploy it, the driver would pull out in front of the attacker and turn it on."
It weighs 400 pounds -- it's the size of a large copy machine -- and uses 300 kilowatts of power that's generated by a gasoline-powered turbine.
"To deploy it, the driver would pull out in front of the attacker and turn it on."
...with 300 KW of microwave energy? Good luck with starting a family after that.
For varying degrees of "works".
It's not just efficiency, it's basically ease of operation. One of the big things about modern cars is they are "twist and go". You twist the key (or push the button nowadays) and the car goes. Doesn't matter if the engine is hot (vapor lock is not an issue), very cold, or any other thing, including poor fuel. You want it to go, it goes, and unless something is very wrong, it will go. (You can even shoot out cylinders and while it stalls the engine, you can have a V8 engine with 6 dead cylinders still barely run. It's not happy, but the computer is able to compensate and get you home, albiet slowly).
Anyhow, did you wonder why it took 300kW to do it? It's because an ECU is very well shielded to begin with - the metal body of the car already is a great faraday cage. But the ECU is also encased in a metal body because it's a very challenging environment with a lot of stray RF caused by all the high voltages around.
In fact, if you're willing to settle for post-millennium vehicles, disrupting the keyfob-car communications will generally be far easier - the windows in the passenger compartment don't generally block RF, and the signal levels are weak since keyfobs are powered by itty coin cell batteries with poor peak power performance, so they don't have much transmit power. (I had to replace the battery in my keyfob - it still measured 3V, while batteries that are generally dead used in PCs measure pretty damn close to 0.5V. Heck, even my watch which died suddenly had a battery that measured around 0.5V. No doubt the battery was low, so it couldn't supply the necessary power for the transmitter)