You know the old bit about putting tin-foil on your head to keep the government signals out of your brain? It turns out cladding your head in tin-foil has the opposite effect.

Researchers at MIT, using a network analyzer, tested the impact of tin foil helmets on receptivity of radio-frequency signals. They highlight the method and results in the study abstract:

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.

While their conclusion is a bit tongue-in-cheek, the irony of foil helmets increasing reception of government-reserved radio frequencies is certainly not lost on us.

On the Effectiveness of Aluminum Foil Helmets: An Empirical Study