Nov. 29, 2007 -- The same microwave radiation that reheats pizza can be used to fry the electrical systems in cars, stopping them dead in their tracks.

This struck me as a bit odd, because what microwave ovens do is vaporize water, and anything powerful enough to kill a car by vaporizing the water in it would probably kill it's passengers. So I dug deeper.

The technology uses the same kind of energy used in microwave ovens, but at a different frequency. Ovens typically operate at 2.45 Ghz, whereas the high-power car-stopping system is at 300 megahertz. In both cases, the radiation is above common radio frequencies and is not harmful to humans.

OK, technically a 300 megahertz signal is called "microwave" because anything from 300 megahertz to 300 gigahertz is considered "microwave." However, there is almost no real technical relationship between whatever this 300 megahertz signal is doing to your car, and what microwave ovens do. There is also no relationship between the reason microwave ovens are safe and the reason this car blaster is safe. Microwave ovens are safe because they are sheilded. This blaster is safe because it operates at a completely different frequency that has totally different characteristics. I'm also not sure what they mean by "In both cases, the radiation is above common radio frequencies." 300 Megahertz is in a band reserved in the United States by the government for 2 way radios and meterology. All kinds of radios operate at 2.5 gig, including 802.11b and lots of cordless telephones.

Having said that, this is kind of like a HERF gun. Its a focused radio beam with high enough power and frequency that it has the capacity to fry electronics. Its a cool idea. Its just being presented in a way that seems ridiculous to anyone who understands radios.

Tatoian thinks that with the proper funding, Eureka Aerospace can shrink the device in less than two years to a 50-pound appliance that looks like a plasma television and can disable cars from 600 feet away.

I wonder how big it is now and what it's current range is...

Nov. 29, 2007 -- The same microwave radiation that reheats pizza can be used to fry the electrical systems in cars, stopping them dead in their tracks.

Decius wrote:

This struck me as a bit odd, ... So I dug deeper.

I'm also skeptical of stories like this, but for a different reason. Why is this in the news now? There's nothing newsworthy in the story. None of this is recent work by the contractor, although it looks like the reporter did speak to the company recently. (Or, rather, the other way around, as seems likely.)

According to the company's web site, linked at the bottom of the article, those tests with LAPD were conducted in April 2004.

Decius wrote:

It's a cool idea. It's just being presented in a way that seems ridiculous to anyone who understands radios.

Well, the company offers more details on their high-power electromagnetic system (HPEMS), including a functional block diagram. It's not exactly a sophisticated hardware concept. Generating enough energy and pointing isn't a Hard Problem. The difficulty lies in crafting a signal that will have the desired effect, with high probability, and with low probability of undesired side effects. It seems apparent that they don't have a general solution, and they don't have a plan for one. They can talk endlessly about miniaturization, but no one will be interested unless the system is reliably effective against an arbitrary target of interest.

Tatoian thinks that with the proper funding, Eureka Aerospace can shrink the device in less than two years to a 50-pound appliance that looks like a plasma television and can disable cars from 600 feet away.

Decius wrote:

I wonder how big it is now and what its current range is...

That was in the article:

The current prototype is about 5 feet long, 3 feet wide, a foot thick, and weighs just under 200 pounds. ... In tests on four vehicles, the researchers were able to disable cars from 10 to 50 feet away.

(The company says there were six cars, but who's counting?) Also, what the reporter doesn't explain, but which is clear from Eureka, is that in order to successfully disable the test vehicles, they first had to attach a meter to each vehicle's Electronic Control Module while it was being illuminated, looking for vulnerable resonances. The discrepancy on the number of vehicles probably means that for two of the vehicles, they were unsuccessful in finding any frequencies sufficiently "vulnerable" so as to disable the vehicle from a distance of at least 10 feet.

Of course, "now" is relative; the "news" column on their home page is still highlighting press releases from mid-2005.

Decius wrote:
This struck me as a bit odd, So I dug deeper.

I wonder how big it is now and what it's current range is...

... wait, wouldn't the inverse square law make this really really really impracticable for long distances? How much power do you need to pop a car's electronics? How does that scale with distance?

Acidus wrote:

Decius wrote:
This struck me as a bit odd, So I dug deeper.

I wonder how big it is now and what it's current range is...

... wait, wouldn't the inverse square law make this really really really impracticable for long distances? How much power do you need to pop a car's electronics? How does that scale with distance?

They are using a LOT of power, which means their explanation of the safety of the device is not just nonsentical, it may be incorrect. I certainly wouldn't recommend standing directly in front of thing thing!