Lots of interesting pictures in the original
On the Effectiveness of Aluminium Foil Helmets: An Empirical Study
Ali Rahimi1, 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
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 ClassicalThe Fez
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
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).
Test subjects during a dry run.
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.
A typical attenuation trace form the network analyser
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. Conclusion
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
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.
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