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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."
Really, I had this idea a very long time ago. You don't need the full 300kw power system if you use a pulsed maser instead of a constant broadcast. That means you can use some kind of storage system with a smaller input, such as an air-coil resonant tank, or a super-capacitor array. You just need to be able to deliver the 300kw on each pulse. It takes time for the ICM to reboot; you dont have to keep roasting its ground lanes with signal. You just have to make it malfunction and restart in a reasonable interval. 1hz pulse width would be sufficient.
Assuming these tools are driving their emitter nonstop, that would let you use 1/60th of the power generation hardware, or ~5kw power system. Even less if you use a 2sec interval instead of 1.
For some variations of the pulse timing, a second alternator on the delivery vehicle would be sufficient; the bulky part would be the super capacitor array, which could be installed in the trunk, or in the rear seats.
The referenced idea I had called for a klystron resonant cavity with a pulsed electron beam, and a low power reference microwave signal produced by a small magnetron. As long as pulse duration time is some whole integer product of the reference signal frequency, it should work fine.
Hilarious that an idea I had as a teenager in the 90s is being seriously considered here though. LOL.
That shielding won't save you, and is actually the point! The shielding absorbs the energy, causing a large transient voltage spike in your car's electrical system. That causes the ECU to crash, because it isn't designed for those conditions.
One of the key things to understand here is that the car only has two electrical connections, battery + and battery -. Battery - is often called "ground," it will tend to be at local ground because it is referenced to the vehicle chassis which will likely be at ground potential when you start the car. But it doesn't have a third wire with an actual Earth connection, and the wheels are usually electrical insulators. What that boils down to is that shielding works by converting the RF interference into a short voltage spike, some of which is converted to heat in the ECU and any other electronics with voltage regulation. All the devices in the car are already expected to survive "double battery condition," which is when the tow truck driver gives you a jump start using 24V, which is really 28V+ because their engine is running and their battery is charging voltage. So there is a huge amount of voltage margin and the shielding works well without even having system-wide voltage regulation. But in the extreme case, as with this device, you eventually overload the ECU's voltage regulation, and since the circuit is designed to be robust, it simply crashes and reboots as soon as the spike dissipates. Repeated use could easily damage a vehicle, though.
For protection against this, I'd want to try something low-tech like a wire brush connected to the chassis that can drag on the ground slightly, so that voltage spikes can find a path to Earth instead of getting stuck in the circuit.