[xxpor]

I don't get the physics of how it could possibly be a microwave weapon.

Microwaves (mostly) just heat things up. Even the area denial "giant microwave generator" on a truck weapons simply make you feel like you're burning up. How could they possibly find a frequency or modulation that

A) Only affects the brain

B) Isn't stopped by exterior walls

C) Doesn't cause heating effects on the rest of the body (and everything else around you, or at least between you and the source of the radiation)

D) Isn't incredibly obvious when it's sitting around. Either this would have to be fairly high power, i.e. physically large, or it would have a high gain antenna (also large). If the power is low, it'd have to be close to the victim, like in the same room. The other problem is how do you hide the antenna? It can't sit in a van because the metal exterior would attenuate it.

[admiralspoo]

It depends on the frequency. The brain is mostly water, but there are clear differences in the dielectric constant of air, the skull (bone) and the sweet delicious gray matter inside the cavity. By tuning the frequency of the waves, you can set up resonances in the cavity.

For a related effect, see https://www.youtube.com/watch?v=wCrtk-pyP0I

[01100011]

From the report:

"Frey reported these symptoms with an RF source transmitting at 1.3GHz(which provides the greatest absorption depth into cortical tissue)..."

So they are implying that not all RF is stopped by the skin and some does penetrate deep enough to reach the brain. I don't suppose it will be long until some shortsighted YouTuber tries this as the experiment would not be hard to replicate at all.

[ajsnigrutin]

Due to skin effect, most of the power is absorbed in the outer layers (skin mostly), and that causes 'warm/hot/burning' feeling, before doing anything else to your body.

[K0balt]

That's not what the "skin effect" refers to, and penetration of tissue / heating is completely dependent on frequency.

[xxpor]

Hm resonance inside the skull isn't something I'd considered, that's a fair point.

[CamperBob2]

Because it's not an issue. A bag of saltwater makes a really terrible resonant cavity.

[emmelaich]

You'd think grapes would make a poor resonant cavity too. But you can create plasma with grapes in a microwave oven.

[CamperBob2]

Yes, and that's precisely because they are so lossy. It's not a resonant effect. You're just taking advantage of the grape's cross section being roughly a quarter-wavelength at 2.4 GHz, which allows the magnetron to dump a ton of power into it.

It's analogous to using a couple of forks to operate a pickle from 120V.

[MacsHeadroom]

>roughly a quarter length

Is that not resonance?

[the_only_law]

Before I act like an idiot and go do this, is there any significant safety risk or major risk to the equipment in doing this?

[CamperBob2]

Should be fine as long as you put a cup of water in the microwave alongside the grape. They aren't really meant to run empty, and microwaving a single grape would be basically running it empty.

[lend000]

All 4 of your points could be easily explained if the device was designed similar to a "gamma knife" [0].

With a gamma knife, a number of lower power beams converge on the target from different locations to create a higher intensity at a calculated location, and everywhere else the intensity is low enough to write off.

[0] https://en.wikipedia.org/wiki/Radiosurgery#Gamma_Knife

[sudosysgen]

A gamma knife-type thing would require much higher frequencies than are compatible with the theory because otherwise you get diffraction since the wavelengths are so large. It's very unlikely you'd be able to do such a thing with 20-12 cm wavelength radiation, the calculated location would be meters big and it would be detectable everywhere.

[lend000]

Masers have been around longer than Lasers [0].

I don't know how building walls would affect coherent radiation at various frequencies, but if 80% of the energy made it to the destination, the other 20% could explain the variety of symptoms experienced in the room.

[0] https://en.wikipedia.org/wiki/Maser#:~:text=A%20maser%20(%2F....

[sudosysgen]

The only maser that would fit the bill is a hydrogen maser with a frequency of around 1.4Ghz.

That's a wavelength of 21cm.

That means that your beam waist is never going to be less than 21cm, which means that your beam divergence is going to be of at the very minimum 0.21/pi radians = 3.8 degrees, likely twice that.

That's just not targeted enough to be able to hide the massive EM interference it would cause (like, instantly destroying electronics). And also, if the transmitter was 200 meters away, it would have to be dozens of meters big, assuming you got some lending system. Otherwise, it would still be huge, but it would also spew radiation at a truncated cone with a radius in the meters.

Also, building walls would certainly deflect a lot of the radiation and cause decoherence but also heating and destruction of electronics.

In any case, if it was any kind of EM weapon at a suitable frequency, it would be incredibly detectable and we wouldn't have this discussion.

[bjourne]

But for neurosurgery the head is held in place and the gamma knife does not need to be hidden. Presumably, the microwave transmitters of a conjectured gamma knife would need to be portable and able to operate without even being in the same room as the target's head.

[ruined]

Microwaves have much lower energy than gamma radiation, and brain damage requires much cruder fidelity than brain surgery.

The experience described by targets seems to indicate room-scale effects.

[bjourne]

We're still taking about imagined devices pinpointing targets' brains from large distances and through walls. I find it hard to believe that these devices would be that accurate and never miss and, say, accidentally hit someone's eyes or neck and cause obvious tissue damage.

[jellicle]

But now the problem is convincing large numbers of people to stick their head into a machine where 200 individual beams can be focused on their skull, and then forget they ever did so.

https://www.mayoclinic.org/tests-procedures/brain-stereotact...

[infoseek12]

I can’t address many of your objections but I don’t think putting it in a van would be a problem. Organizations sometimes use fiberglass body panels that look like normal metal ones but are transparent to RF in these kinds of situations.

[elihu]

I sort of assumed that if this is an RF weapon the attackers would just have a hotel room directly above or below the intended target, maybe even some structural modifications to the floor/ceiling.

[nitrogen]

Not that it's proof or anything, but supposedly ICE or a similar org has undercover backscatter XRay vans. Don't remember where I read that, but it was years ago.

[ceejayoz]

Definitely a thing. The NYPD has them as well.

https://www.propublica.org/article/drive-by-scanning-officia...

> ABC News reporters Richard Esposito and Ted Gerstein provide one of the few accounts of the backscatter van in a book they wrote chronicling a year inside NYPD's bomb squad. Describing the security ahead of President Bush's motorcade to the 2004 Republican convention, they wrote that every vehicle entering the street in front of the hotel was ordered to drive between two unmarked white vans, which X-rayed each vehicle for bombs.

[janekm]

Driving between two vans suggests that it's not back-scatter though... "Just" low energy x-ray probably?

[derefr]

Collimated microwaves (i.e. a maser) pointed directly at the skull, from a distance, through a window, I'd assume.

What are the reported symptoms from military radio engineers standing in the transmission path of high-power/long-distance ship-to-ship microwave links?

[ajsnigrutin]

To directly point radiwaves, you need very very high frequencies, and with skin effect, those don't go very deep into a humans head (we're talking millimeters or less here).

[kurthr]

You mean like into ears? I mean that's the reported symptom... your ears are your skin so are your eyes.

[xxpor]

Trying to align a microwave link on a ship that's floating (i.e. not completely steady) sounds like a horrible nightmare.

[sudosysgen]

It's complete bullshit. If there actually were RF attacks of such huge intensities, the US would have trivially recorded them.

Yet that didn't happen. I don't see any reason why no measurements and proof would be measured given the extreme ease of doing so, except that it just didn't happen.

[Sporktacular]

"US would have trivially recorded them."

Depends on the frequency range being continuously monitored. If it's above the usual signals intelligence range there's a good chance it wouldn't have been recorded.

"Yet that didn't happen."

And we wouldn't know if it had. Holding on to what you can detect and attribute carries advantages too.

[sudosysgen]

We're talking about repeated attacks at around 1.4Ghz, so not only within the range of SIGINT, but it would literally fry your phone, and they were supposedly repeated.

As for the last one, if there was proof, then the State Department wouldn't abandon the theory, and such wildly speculative and substance-less research wouldn't be commissioned.