RadioGirl

Agree; that's a much clearer summary of what I was trying to say about "societal concerns" above. I also repeat my concern about not being able to watch my belongings while being scanned; at this point my BIG worry would be having my handbag or laptop stolen.

Seat1A

i've been thru the MMW/ATD a couple of times now -- each time, i beat my belongings to the far end of the belt.

imo, the only reason remaining to opt out of MMW/ATD is as a protest against TSA in general. that's a fine reason, but i'm not going there any more with that machine. (still not going into the blue screening of death, tho... (saw one failing to boot windows recently, and the parallel amused me..))

guflyer

Are there still some health concerns regarding MMW? After reading about the Los Alamos study, I have remained concerned that while something has not been found so far, it may be found later.

tev9999

Just went through the gumby MMW at DTW (McNamara lower level). Only one other person at the checkpoint around 9 pm. Two false positives and a zipper pull.

Left jeans pocket - TSO asked if I had anything in my pockets, said no, and tried to turn my pockets inside out - but these pants don't do that. He didn't bother checking any further. For the record there was nothing in my pocket.

Center of chest - I'm wearing a 1/4 zip pullover with a metal tab - I'm assuming that is what it picked up. I'll give them this one as a real catch. Not touched by TSO. Could have been concealing something underneath.

Left shoulder - barely touched by TSO, nothing there.

I made a comment about the horrible false positive rate and he just said "have a nice night".

Conclusion: The false positives are massive. This is only my third time through MMW and I have had 2, 1 and 2 false positives. TSOs are not even bothering to clear them any more.

RadioGirl

No, not really.

The Los Alamos paper relates to frequencies around 1000 GHz (= 1 THz) and fairly high powers, while the MMW NoS is 24-30 GHz and much lower powers. The paper is based on computer modelling of effects, not on actual measurements of exposure (it's a valid approach, but it has its limitations.) Furthermore, the Los Alamos paper itself is quite hesitant in relating exposure to "effect" and "effect" to damage. The conclusions are (appropriately) very cautiously worded. Finally, other researchers have disputed the methodology of the paper. I'm a radio engineer and not a biologist, so I won't go into any more detail, but that's my understanding of the research.

More generally, MMW is similar enough in frequency and low enough in power (I've satisfied myself on both these points from independent sources) compared to other radio systems in common use that there's no real basis for concern. The conventional wisdom at these frequencies is that the only health risk is when the power is high enough to heat the skin or underlying tissue, and the MMW is many orders of magnitude below that.

doober

You're supposed to be housecleaning!!!!

RadioGirl

Busted.

Wimpie

I totally concur with RadioGirl, and am an RF engineer as well. I posted this rather lengthy explanation to my Facebook group last July, and will repost here:
A little primer about radio and x-rays.

Radio consists of radiated waves of different frequencies. These frequencies run from DC up to the far infrared frequencies. More than 100 years of research and experimentation has pretty much proven that "radio" waves have no mutinogenic effects on tissue. At lower frequencies, these waves pass harmlessly through tissue and apparently do no damage, even at very high power levels. At very high frequencies (microwave), these waves seem to be absorbed and there is a heating effect on tissue. Tissue destruction can occur if the power level is high enough, but even at these high levels damage is due to burning and destroying tissue, not mutinogenic effects, like cancer.

High power microwaves are used to cook stuff, like TV dinners, because the waves are absorbed by water-bearing items and converted to heat. The same frequency waves at much lower levels appear to be harmless, causing only slight heating without destruction of tissue. At even lower levels, history has proven them completely harmless.

We are constantly bombarded by radio waves, and can't escape them. Just think how many radio and television stations you can receive at your house, how many cell phone towers, microwave links, satellite dishes, etc there are in your locale. Even the automatic door openers at the market and bank are beaming microwaves at you to "see" you and open the door. Your computer emits low to medium frequency radio waves, in addition to the wireless adapter which transmits microwaves. Your TV emits spurious radio waves. Every CPU in your phone, car, digital appliance, etc emits radio waves of some frequency or multiple frequencies. Your microwave oven even leaks a small amount of microwaves. Your cell phone is a microwave radio as well.

It is accepted in the scientific community that ordinary radio waves are harmless below a certain amount of power (expressed in W/CM2). Because of the heating effects of higher frequencies (microwaves), the safe power levels are much lower than at lower frequencies. Even above the "safe" limit, cancer is not induced. There are no known MUTINOGENIC effects.

While I completely disagree with naked body scanners, and will never subject myself to one, the frequency and power levels employed are clearly a non -issue. Your cell phone and the wireless adapter in your laptop are thousands of times more powerful, and they are generally considered safe. There is no proof that cell phones are dangerous, although millions have been spent researching the matter, but there is no repeatable, scientific evidence.

X-Rays, however, are a completely different animal. Their frequency is so high, that they are considered "energetic particles", not waves. They interact with tissue knocking atoms out of their orbits, and have known, certain mutinogenic effects. They absolutely induce cancer, although there is some argument whether or not there is a "safe" threshold. X-ray body scanners operate below what some scientists consider this safe threshold, but there is no universal agreement about this. Therefore it is prudent to avoid unnecessary x-rays from any source, unless there is clear benefit to be derived, like medical and dental x-rays.

Remember that the US and other countries outlawed Freon, with the rationale that depleting the ozone in the atmosphere would increase the UV radiation on the ground, causing more cancers in people. These are the same bozos beaming x-rays at us, certainly causing some cancers, but nobody knows how many. For this reason, x-ray scanners need to be immediately abandoned, and the EU has outlawed them for Europe. Only the US and UK have been duped into using these machines, as they do produce higher image quality than the MM wave type, and they clearly had better lobbying. Remember that Michael Chertoff was the former head of TSA before promoting these things - he has the right "connections".

All that being said, the MM wave scanners with auto detect software appear to be safe for your privacy and safe for your body, providing there is no raw image storage or review. However, they are expensive and slow as well as ineffective, causing lots of false positives due to medical devices, folds of fabric, lint in pockets, etc. This is the WRONG METHODOLOGY for finding explosive materials! The X-ray type scanners need to be pushed into the ocean immediately. Better yet, push them all in the ocean and bring on the dogs and save a BIG PILE of money!

N965VJ

No surprise; imagine the outcry of protests if a large number of people that didn't opt-out ended up with a grope anyway. I wonder how many things like knives are making their way into the sterile are now, carried by people that forgot they had them.

InkUnderNails

Opposite experience here. Five times through. Zero positives, true or false.

RichardKenner

I don't follow your last sentence since there's no one "on site" to view the image containing the anomaly. If they were saving images for QA purposes, I don't think it would make sense to just save the ones with anomalies or just the ones without: it would need to be some of both.

InkUnderNails

You may be right.

My logic is this: These devices are capable of providing a piece of evidence in a potential criminal prosecution. If the computer detects no anomaly, then it has decided there is no potential evidence and the data goes away. If it does detect an anomaly, it should at least keep the data required to construct the image until it is no longer a potential bit of evidence. To do otherwise would be nonsensical from a law enforcement perspective and I would expect it. When I am cleared, I also expect the bits and bytes to go to their cyber graveyard somewhere.

RichardKenner

We've been through this before. If a prohibited object is detected, the only evidence required is the object itself. Otherwise, how could somebody be convicted if the WTMD detected it?

gojirasan

As I've stated before I don't really have a problem with MMW+ATR machines. The surrender position is probably the worst aspect of it. Of course when you have angry goons with the IQ of a cockroach manning the things all bets are off. But the machine itself is not dangerous and the images are not only not viewed by a human, but probably not even viewed by a machine as RadioGirl pointed out.

Yes, they are ineffective. Yes they are overpriced. But I don't really find them overly invasive. A patdown generated by a false positive could be overly invasive, but I don't find the machine itself to be so. Would I vote to get rid of them? Yes, but it would not be due to their invasiveness. It would be due to the winning combo of their excessive cost to taxpayers and their ineffectiveness as proven in German testing. If they had been effective Germany would have kept them.

As RadioGirl pointed out that Los Alamos 'study' wasn't really a study at all. It was a mathematical model with plenty of assumptions. And the conclusion was soundly refuted just a few months later in another paper.

Technically, I'm not even sure that the L3 MMW machines even emit millimeter waves. Wavelength can be conveniently measured in centimeters up to about 29.98 Ghz which corresponds to 0.99 cm waves. Basically millimeter waves don't start until 30 Ghz and from what I've heard the L3 machines may not actually reach that frequency. They do get close though. But it's a long way from 27 Ghz (or whatever) to 95 Ghz of the US Army's Active Denial System weapon.

Pesky Monkey

So in other words we should just have a pretend scanner that automatically detects a "prohibited" item for every passenger so that if a "prohibited item" is really found we have an excuse for strip searching the passenger.
That way, we have no record of why we strip searched the passenger other than "the machine beeped".
I think that's what we already have.