Electromagnetic shielding and phantom pain [tech corner]
Electromagnetic interference or EMI is supposed to contribute to phantom pain. We do not know why that is. Other theories attribute phantom pains to an efference/afference dysbalance. Apparently, mirror therapy works but not in all cases.
But, what do we know.
What we know is that both FARABLOC and UMBRELLAN are cheap metal mesh stump socks that are sold for a lot of money. Apparently studies "confirm" that "they work". The basis for their function is according to the sales claim that they "shield" EMI. On the FARABLOC website, they state that "Farabloc is a cloth like material that has been tested and proven to provide high EMF protection when wrapped or placed on the area of injury."; some research covering FARABLOC also found that it works against sore muscles which hints at the possibility that warmth (heat loss insulation) could be at work; given my stump always being colder due to poor circulation it is a fact that I may benefit from wearing a wool or cotton sock over it (of course not an overpriced metal mesh). UMBRELLAN is advertised with "Umbrellan® is a unique, patented knitted fabric that combines with an excellent electromagnetic screen" and "Das patentierte Umbrellan kann elektromagnetische Strahlungen aus der Umwelt abschirmen".
That, however, is not plausible. Either the shielding material is at least 3 mm thick and made of a suitable substance such as copper and contains no holes (i.e., also no hole for the arm). Or, the metallic cover has to be grounded.
Any un-grounded thin metallic cover - think "tin foil hat" - will more likely act as an antenna than as a deflector. That means, that by wearing a metallic mesh fabric without proper grounding, you will likely not deflect any substantial amounts of electromagnetic interference.
Tin foil hats come to mind that "use" the same "design" as these allegedly phantom pain reducing metal mesh socks. Also, tin foil hats (if not properly grounded or built) will more likely act as an antenna - which however has been scientifically shown (below).
In 2005, a group of MIT students, prodded by "a desire to play with some expensive equipment," tested the effectiveness of foil helmets at blocking various radio frequencies. Using two layers of Reynolds aluminum foil, they constructed three helmet designs, dubbed the Classical, the Fez, and the Centurion, and then looked at the strength of the transmissions between a radio-frequency signal generator and a receiver antenna placed on various parts of their subjects' bare and helmet-covered heads.
The helmets (..) surprisingly, amplified certain frequencies: those in the 2.6 Ghz ( allocated for mobile communications and broadcast satellites) and 1.2 Ghz (allocated for aeronautical radionavigation and space-to-Earth and space-to-space satellites) bands.
While the underlying concept is good, the typical foil helmet fails in design and execution. An effective Faraday cage fully encloses whatever it's shielding, but a helmet that doesn't fully cover the head doesn't fully protect it. If the helmet is designed or worn with a loose fit, radiofrequency electromagnetic radiation can still get up underneath the brim from below and reveal your innermost thoughts to the reptilian humanoids or the Bilderberg Group.
On the Effectiveness of Aluminium Foil Helmets: An Empirical Study
Ali Rahimi 1, Ben Recht 2, Jason Taylor 2, Noah Vawter 2 - 17 Feb 2005
1: Electrical Engineering and Computer Science department, MIT.
2: Media Laboratory, MIT.
Among a fringe community of paranoids, aluminum helmets serve as the protective measure of choice against invasive radio signals. We investigate the efficacy of three aluminum helmet designs on a sample group of four individuals. Using a $250,000 network analyser, we find that although on average all helmets attenuate invasive radio frequencies in either directions (either emanating from an outside source, or emanating from the cranium of the subject), certain frequencies are in fact greatly amplified.
These amplified frequencies coincide with radio bands reserved for government use according to the Federal Communication Commission (FCC). Statistical evidence suggests the use of helmets may in fact enhance the government's invasive abilities. We speculate that the government may in fact have started the helmet craze for this reason.
It has long been suspected that the government has been using satellites to read and control the minds of certain citizens. The use of aluminum helmets has been a common guerrilla tactic against the government's invasive tactics . Surprisingly, these helmets can in fact help the government spy on citizens by amplifying certain key frequency ranges reserved for government use. In addition, none of the three helmets we analyzed provided significant attenuation to most frequency bands. We describe our experimental setup, report our results, and conclude with a few design guidelines for constructing more effective helmets.
The three helmet types tested: The Classical, The Fez, The Centurion. We evaluated the performance of three different helmet designs, commonly referred to as the Classical, the Fez, and the Centurion. These designs are portrayed in Figure 1.
The helmets were made of Reynolds aluminium foil. As per best practices, all three designs were constructed with the double layering technique described elsewhere . A radio-frequency test signal sweeping the ranges from 10 Khz to 3 Ghz was generated using an omnidirectional antenna attached to the Agilent 8714ET's signal generator. The experimental apparatus, including a data recording laptop, a $250,000 network analyser, and antennae. A network analyser (Agilent 8714ET) and a directional antenna measured and plotted the signals. See Figure 2. Because of the cost of the equipment (about $250,000), and the limited time for which we had access to these devices, the subjects and experimenters performed a few dry runs before the actual experiment (see Figure 3). The receiver antenna was placed at various places on the cranium of 4 different subjects: the frontal, occipital and parietal lobes. Once with the helmet off and once with the helmet on. The network analyzer plotted the attenuation betwen the signals in these two settings at different frequencies, from 10Khz to 3 Ghz. Figure 4 shows a typical plot of the attenuation at different frequencies.
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.
The helmets amplify frequency bands that coincide with those allocated to the US government between 1.2 Ghz and 1.4 Ghz. According to the FCC, These bands are supposedly reserved for ''radio location'' (ie, GPS), and other communications with satellites (see, for example, ). The 2.6 Ghz band coincides with mobile phone technology. Though not affiliated by government, these bands are at the hands of multinational corporations. It requires no stretch of the imagination to conclude that the current helmet craze is likely to have been propagated by the Government, possibly with the involvement of the FCC. We hope this report will encourage the paranoid community to develop improved helmet designs to avoid falling prey to these shortcomings.
The authors would like to thank Andy (Xu) Sun of the MIT Media Lab for helping with the equipment, Professor George Sergiadis for lending us the antennae, and Professor Neil Gershenfeld for allowing us the use of his lab equipment. (Please direct any queries to the authors, NOT these folks)