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Comment by russfink | Hacker News Reader

Is there a defense against this kind of thing? Not to sound cliche, but would a tin foil hat work?

A simple experiment result published by the MIT Media Lab, found tinfoil hats are not really effective. https://web.archive.org/web/20100708230258/http://people.csa...

> For all helmets, we noticed a 30 db __amplification__ at 2.6 Ghz and a 20 db amplification at 1.2 Ghz, regardless of the position of the antenna on the cranium. In addition, all helmets exhibited a marked 20 db attenuation at around 1.5 Ghz, with no significant attenuation beyond 10 db anywhere else.

Full electromagnetic shielding of the entire building perhaps? Like those at the NSA headquarter. It should give you a heavy attenuation on the microwave frequency.

BTW, why don't the intelligence agencies install a software-defined radio in suspected US embassies to log the entire microwave spectrum? It will definitely yield something.

You don't even need SDR... a really simple LED and a few variable antennas would do a good job into the GHz.

For detection, yes, it can be done by an extremely simple circuit. But you would need the raw I/Q sample data over a broad frequency range to perform a technical analysis to identify the nature of the microwave. Here's when a SDR comes handy.

The LED just reveals power (detection of radiation over many visible orders of magnitude) ... it doesn't need to detect coherent I/Q, because I don't think neural effects are sensitive to phase either. Selectively cooking a brain would require relatively high power and beam forming, but not high data rate. Audio frequencies are visible (use multiple band pass filters if you like) .

You'd also want a controlled test source so you'd know if the attacker had burned it out.

Do you need a Schottky or will the plain LED work?

With the Schottky you will get better low power detection (lower forward voltage 0.18V vs 1.8V), but it doesn't inherently indicate activation (you'd want an electret or piezo speaker at least) with the same dynamic range as your eye is capable of with an LED. Of course if you have an RMS power meter with uW resolution it will be OK... but LEDs are really good.

That MIT article is bunk. Everyone knows you need a diffraction grating, to diffuse fortuitous signals.

They didn’t even try produce effective results.

Back in (one of?) the very first paper(s?) on this stuff, Frey actually pointed out that a 2x2 piece of flyscreen (of some density, I forgot which) on the temporal lobes blocks the EM/RF hearing effect. But, as I pointed out in another comment, two distinct effects exist:

One that induces EM/RF hearing, and one that induces tissue damage.

I’m not sure that tin foil hat can protect you from lousy journalism based on speculations without any evidence or even clues.

They say that some experts in somewhat related field now agree that the previous speculations based on non-evidence might be somewhat plausible. You’re going to need some military grade tin foil hat for that.

> I’m not sure that tin foil hat can protect you from lousy journalism based on speculations without any evidence or even clues.

I’m certain it can, at least if it’s large enough to cover eyes and ears and thick enough to muffle sounds.

I would guess a faraday cage or faraday helmet would work for sure, maybe even just special screens on the outside of the building or in the walls/windows.

In my limited experience with RF (from ham radio, which includes microwave work though I haven't done any personally) it's very easy to block radio signals even inadvertently, let alone when you really put your mind to it.

Water will shield you I suppose.

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