Active Denial System, A directed-energy weapon

[waveguider]

Discussion on Protection against directed energy weapons.

I tried searching for any other threads on protecting oneself from ADS but found none, I think it is only a matter of time until almost every government will have this system in it's arsenal and may go as far as to track and torture individuals it believes to be a threat with it.
Imagine a person running for president that the existing government wants out of the race or wants to blackmail, Then imagine what they could do with this system and how easily discredited the candidate or threat would be when he tries to expose the blackmail or torture?

I do not like to link to wikipedia but if you haven't heard of this system please take a look http://en.wikipedia.org/wiki/Active_Denial_System


I originally started thinking about making my own Faraday cage incorporated into clothing to protect myself from the possibility of encountering ADS. Of course one could use Aluminium space blankets stitched inside clothing but imagine how hot and uncomfortable that would get!
So the only practical alternative I could think of is Faraday caged clothing, however I came along a few snags that I would like some assistance with:

(1) I have read some articles stating that a faraday cage needs to be grounded to work effectively and others stating it is not needed, I would love some clarification on this, like for example airplanes are not grounded when flying yet can survive lightning strikes but most microwaves have their front Faraday cage grounded and most FEMA buildings have their cages grounded as well.
I have read, over time, charge will begin to accumulate on a unearthed Faraday cage and thus it will start to emit it's own EMF negating the whole purpose of having the cage, I'm not sure if this is a major snag as it is unlikely one would be in direct line of the ADS for too long, how long would render the Faraday suit ineffective however is a major unknown.

Most microwave ovens work at around 2.5GHz which corresponds to a wavelength of ~12cm lambda= c/f. Theoretically any Faraday cage with gaps less than this wavelength will start to block the EM waves, however as you can probably tell from looking at your microwave door the gaps are at the max ~1mm wide or approximately the wavelength/100. Extrapolating this rule of thumb to a shield for the ADS means a gap of 3.16mm/100 or 31.6 microns/ 400 mesh.
I was successful in finding mesh that size but the preferred copper was too expensive so stainless steel is probably the best bet
http://www.twpinc.com/twpinc/control/product/~category_id=TWPCAT_12/~product_id=400X400S0010W48T
This is relatively expensive as the average skin surface area is 2m^2 or 22ft^2 and at ~$20 a square foot! even still successfully joining the strips together to ensure electrical conductivity may prove extremely difficult.

Luckily I stumbled upon this site:
http://www.lessemf.com/personal.html
It sells clothing products that claims ''99% RF attenuation over the frequency range from 800 MHz to 18 GHz.
Unfortunately as mentioned above and in wiki the ADS system is said to emit microwaves at 95 GHz, The mesh sized is not disclosed on the EMF protection site but if I use the lambda/100 rule rule for 18GHz then the mesh would be 166 microns or ~90 mesh and wearing two layers would hopefully equal twice that but that still only equals at the best 200 mesh and I think I need 400 mesh.
However 200 mesh may provide me with an ability to only feel a slight heating effect. It is still a large sum of money to spend on something that may not work. This option would probably be cheaper and more reliable than making my own Faraday suit.

(2)so do you think wearing two layers of the clothing for sale in the link would provide adequate protection?

One major issue of contention is what about being in a lightning enviroment and wearing the suit.
(3)would I produce unwanted lightning streamers? and would the suit adequately protect me from strikes?

[Joxer]

like for example airplanes are not grounded when flying yet can survive lightning strikes

They survive the strike because they dont absorb it. The lightning will still travel to ground. Regarding your question #3, I don't see how anything like this will help you survive a lightning strike.

This is an excellent and timely topic.

[James]

I vaugely recall posting something on the forum about a coat (for women) with conductive fibers woven into it. the Fibers IIRC were copper coated and manufacture by 3M. I'm a bit fuzzy about it, as it has been a while.

[Hinckleyforpresident]

A Faraday cage must be grounded for it to work. Grounding a piece of clothing would probably be rather difficult to do...

[AliasBlast]

Interesting topic! From what I understand, a Faraday Cage does not have to be grounded to block and protect EM radiation, but they often are to prevent other problems when shielding circuitry.

Protecting yourself from the ADS would require covering your entire body or at least the parts in the EM radiation path. I actually like your space blanket idea. Instead of dressing yourself in expensive wire-mesh clothing, or a suit made of conductive plastic etc, you could just whip out the space blanket and wrap it around yourself (as your running away). They're pretty small and easy to carry around. The problem with this is how long you actually have before the effects are completely felt.

"For the first millisecond, it just felt like the skin was warming up. Then it got warmer and warmer and you felt like it was on fire"

Of course clothing would have the added benefit of protecting your RFID cards and electronics. Now you just have to find a way to field test your ideas :D

[Alexires]

You probably wouldn't need to cover your whole body. You could always put the space blanket under your clothes at the front, leaving the back open to breathe. If you are getting hit in the back you are and running away, which means you'll get away soon anyway, so no point in protecting it.

[Hinckleyforpresident]

Electricity follows the path of least resistance, so if you are grounded, and the cage isn't - "BZZZAP!". However, the cage (if grounded) will convert the EM blast into an electrical surge, which can then be redirected.

[Jacks Complete]

Ok, covering yourself with foil will help not very much. The ADS uses a very directional beam which stimulates the nerves, so you feel like you are on fire. Ideal for harassment and controlling the people without any nasty press footage. "We never even unslung our guns!"

Anyway, the beam will make it feel like your face is burning, and your hands, so covering half your body with foil or anything else won't be much use. A large array of corner cubes would be interesting, though, as a countermeasure, though you might want to ensure you are bulletproof as well. The waveguide is about 4 feet across, so we can assume that the beam is about the same width for a significant distance, so you are not going to be able to shield against this to any great effect.

If you want to try, you want lots of conductivity. You want a thick aluminium foil, or, better, a pure copper mesh. It doesn't really have to be earthed, the wavelengths we are dealing with are in the range where you get what is called "Skin effect" (ironic, huh?) where the electrons on or very near to the surface of the conductor do all the work. This means that you can use a thin layer and get effective protection, as long as it is blocking line of sight.

Earthing isn't needed, as long before the voltage gets very high, it will earth through your legs anyway. The worst that would happen is that you would float up to a few tens of thousands of volts, then discharge in an arc. This would be the same as a static shock. It would be funny if you wired a taser unit to the system to ensure you couldn't be grappled, but that's just a random thought.

Another random thought is that you could try the electrostatic bags made from conductive plastic, though I doubt they would be conductive enough.

[iHME]

It would be funny if you wired a taser unit to the system to ensure you couldn't be grappled, but that's just a random thought.


That has already been done. There was/is this jacket for women to prevent muggers/rapists. The jacket has a inbuilt stungun and the outerlayer of the jacket has conductors on it.

Imagine using that in a crowded concert/bus/metro/anything, interesting things could ensue :)

[Joxer]

From http://www.globalsecurity.org/military/library/policy/army/fm/71-1/711apxlf.htm

Effective defense against microwave radiation emitters entails using the following techniques:

Disconnect all electronic equipment when not in use.
Shield smaller electronic items by placing them in empty ammunition cans.
Employ terrain masking, which provides some protection against microwave radiation.
Limit the time personnel are exposed to microwave emissions.

From http://www.wired.com/science/discoveries/news/2006/12/72134?currentPage=2

The beam penetrates clothing, but not stone or metal. Blocking it is harder than you might think. Wearing a tinfoil shirt is not enough -- you would have to be wrapped like a turkey to be completely protected. The experimenters found that even a small exposed area was enough to produce the Goodbye effect, so any gaps would negate protection. Holding up a sheet of metal won't work either, unless it covers your whole body and you can keep the tips of your fingers out of sight.

Wet clothing might sound like a good defense, but tests showed that contact with damp cloth actually intensified the effects of the beam.

System 1, the operational prototype, is mounted on a Hummer and produces a beam with a 2-meter diameter. Effective range is at least 500 meters


It looks like the only practical defense is to stay off the street, and/or destroy the vehicle or antenna.

[waveguider]

I wonder if Polycarbonate is opaque to microwaves at 95 GHz, if not I suppose the only cheap riot solution to this threat is 1mm thick Al sheeting or indeed many layers of space blankets as kitchen foil rips easily. If one needs bullet protection a polycarbonate backing like common riot shields would be useful, a combination of the two shields above should provide a bit of microwave and water cannon reflection etc.

Is anyone else eagerly awaiting a commercial meta-material cloak?

Just another side idea, are there smoke screens capable of attenuating microwaves? akin to the common Teflon+KNO3+sugar Infrared and visible spectrum screens, maybe the above composition would be adequate for microwaves too?

Although the anti riot forces are most likely going to try and flank rioters with a combination of getting the rioters wet and then cooking them with the ADS. A tight Roman testudo formation of the modified riot shields mentioned above would prove to be effective and may afford the users of the shields the ability to advance. I think Jack's Complete was hinting on an excellent idea superior to the minimum reflection Al sheeting would provide.
A large array of corner cubes
Although I presume these corner cubes are made from glass, and glass may be opaque to microwaves although this could be useful for the smoke screen application mentioned above, micro fine glass or sand for sandblasting dispersed by a small explosive charge may provide a microwave smoke screen not to mention a threat of lung damage from silicosis, testing is needed.
Plastic corner cubes do exist apparently and they are inexpensive too:
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2088

A Functioning Al sheet and polycarbonate riot shield combination with a few added corner cubes could provide not only a case of the operators having a taste of their own medicine, but operators of the system would most likely not be prepared for it, leading to the rioters potentially able to capture the ADS, though when are rioters ever this organized? However I have to say, this was not my intended use of the shielding, I am interested in personal safety not safety while being a public nuisance, if you ask me most rioters are usually asking for it, but of late, I have had to revise this assumption.

Joxer mentioned Wet clothing might sound like a good defense, but tests showed that contact with damp cloth actually intensified the effects of the beam
I cannot understand how the water intensified the skin heating effects. I suspect what is really occurring in these tests is the water is opaque and is thus being heated much faster than the skin and contact with the hot water may have scalded the target, An outer garment of cotton for example with an inner nylon rain jacket could negate the operators attempts at soaking the target and then heating them though I'm skeptical of this tactic.

If I am right and this is the case, the water is opaque to the microwave beam, then I am positive that the KNO3 + sugar comp smoke screen would provide protection against ADS and a high humidity environments would further attenuate the beam.
Also from the wired article Joxer linked to is this gem Sandia National Labs is looking at a small tripod-mounted version for defending nuclear installations, and there is even a portable ADS. And there are bigger versions too...an ADS far more powerful than System 1 has been developed. But details of the exact power levels, range and diameter of the beam are classified.

Am I the only one disturbed by the thought of our sociopathic narcissistic leaders getting a hold of this potentially airborne system 2?

[iHME]

I certainly am. When I first read about these "guardian angel" systems, I was terrified.
One does not have to be a rocket scientist to imagine the potential as a torture device, how you gona prove that you got zapped?
You cant look for burned out receptors, at least not easily.
Though it might burn/damage the outer layer of the skin due to the skin effect.
That could make it detectable.

A "counter attack" could be using a pharmaceutic compound that blocks the brains from receiving the burning sensation/pain.


Enjoy you burning sensation at protests. :)

[3287]

It's a big-ass truck with an effective range of 550m.

So shoot it from 600m.

[iHME]

Shoot the military/police at a protest? Do you want to start a blood bath?
They'd probably open fire at you. IIRC only the military has those microwave systems.

But a interesting idea would be reflecting it BACK at them, thus forcing them to shut it down. That would of cource lead to the development of counter measures from the military/police to shield their troops. Countermeasures that YOU might be able to copy.

A interesting idea would also be "reverse engineering" the weapon and deploying your own. But that would mean dragging a 20 000+ eur frequency analyzer to the zone and identifying the used frequencies. Then one would just have to build a device transmitting sinewave at the desired frequency.
The bad thing is that the system might be working on the millimeter waves (eg. teraherz). Though waveguider mentioned it being 95Ghz, I'm not sure if that is the correct frequency.

[3287]

It is documented as being 95 GHz, but that doesn't mean we're being fed accurate information.

http://en.wikipedia.org/wiki/Active_Denial_System

Citation 5, apparently it's from Popular Mechanics.

[Hirudinea]

I certainly am. When I first read about these "guardian angel" systems, I was terrified.
One does not have to be a rocket scientist to imagine the potential as a torture device, how you gona prove that you got zapped?

It would be a wonderful torture device, burning without leaving any marks, sounds ideal.

You cant look for burned out receptors, at least not easily.
Tough it might burn/damage the outer layer of the skin due to the skin effect.
That could make it detectable.

Mabye it could cause some skin effects, but I think it would be similar to a sunburn, which would probably clear up after a couple weeks, very easy to hold someone until the evidence of torture is gone.

A "counter attack" could be using a pharmaceutic compound that blocks the brains from receiving the burning sensation/pain.


Enjoy you burning sensation at protests. :)

Get wacked out on any good quality opiate and you'll be walking up to the transmitter asking them to roast your weenies. ;)

[Alexires]

Or weiner....

It's a big-ass truck with an effective range of 550m.
Effective range is AT LEAST 500M

A lot of difference between 500m and at least 500m.

Perhaps would use some other kind of EM generator to "cancel" out the signal or augment it so that it doesn't burn you.

[Joxer]

But a interesting idea would be reflecting it BACK at them, thus forcing them to shut it down. That would of cource lead to the development of counter measures from the military/police to shield their troops. Countermeasures that YOU might be able to copy.

I like your idea.

If the beam is that tightly focused, perhaps a parabolic reflector could be used to reflect it right back at them?

I use something similar for wifi connections, when the signal is weak. It's made out of a cheap heat lamp used on farms, and cost me all of $10. While not truely parabolic, it's close enough.

[waveguider]

I've found a video of a reporter using plywood and then a mattress shield to help with protecting himself against the effects of the ADS, the plywood seems effective.

http://www.youtube.com/watch?v=J1w4g2vr7B4&feature=related

Once I watched the video I thought of thick leather shoes coupled with leather gloves and the use of the plywood shield would potentially provide the reporter with adequate protection. Then I thought of the potential of Samurai leather armor. My reasoning behind this is that leather is made out of skin and so it sacrifices itself for your skin, I'm not sure, it might provide adequate protection.