Do tinfoil hats work?


Rick Crammond of British Columbia wrote in to share a test he conducted where he attempted to block a wireless modem’s signals using a stocking cap covered in tinfoil, in essence creating a Faraday cage for his head. While the direct benefit of a tinfoil hat remains unclear, it’s interesting how easily these ever-present signals can be deliberately blocked.

18 thoughts on “Do tinfoil hats work?

  1. Bob A. says:

    Wouldn’t you need to encase your entire head in foil, since you don’t know from which direction the mind-control rays are coming from?

  2. richms says:

    He isnt holding the box that makes the noise when it is in the hat.

    Highly inconclusive that its the had blocking it and not simply the act of not holding the device.

  3. rfenginerd says:

    1. A Faraday cage is an enclosure, per definition. Thus, this is not a Faraday cage, it is more akin to a metal plate. Stop calling it a cage, or Faraday for that.
    2. electromagnetic energy can be blocked in the direction of travel by a plate, sort of, but fringe fields will be present. Actual blockage will be highly dependent on the exact location of the receiver point, the plate, the source direction, RF frequency etc.
    3. Partial blockage only sort of works for far fields, with sources at a far distance. For near fields (such as cell phones close to an ear) the discontinuities in the metal hat and the edge between air and metal can couple with the antenna, actually increasing the electric field locally. Drawing in the RF energy, so-to-speak.
    4. As mentioned, the effect of a hand present makes a huge difference as it is a dielectric as well as ground, depending on frequency.

  4. rfenginerd says:

    As a side discussion: mind control waves are likely not electromagnetic in nature. The brain tissues are simply not dielectrically or magnetically distinctive enough to deposit energy with sufficient resolution to affect brain functionality in a deterministic way. Only if a purposely placed receiver (human or alien in nature) is placed inside the head would electromagnetic energy be useful, for communication and to power the unit. However, it stands to reason that the brain co-located unit would in such a case have bootstrapping firmware to prevent the brain from being able to make or use a tin foil hat, or even conceive of the idea of using tin foil for hats.
    As far as I know, gravitational fields or ESP are not affected by tin foil either.

    I would therefore submit that tin foil hats are, indeed, as useless and as unfashionable as the nay-sayers suggest.

  5. John Baichtal says:

    I love discussions like this.

  6. cyenobite2 says:

    And to all you out there thinking “that’s corny… I would NEVER wear a tin foil hat” – that just goes to show you the mind control is working.

  7. weendex says:

    Here is an interesting read on the topic from a guy at MIT

    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.

  8. rfenginerd says:

    After careful examination of the research presented, I noted flaws in the methodology used in the MIT experiment, as well as in some of the claims and explanations:

    1. No information on equipment calibration dates, methodology are presented. Also, the network analyzer was not calibrated to match the tin foil test setup, as indicated on the display. This undermines the validity of the methodology, the test data obtained and the conclusions.

    2. The setup does not use broadband antennas. Judging from the size of the antenna shown, it would be resonant at 1.3 GHz and harmonics, corresponding with the spikes in gain found.

    3. Issue (2) combined with (1) shows that the trace presented demonstrates interactions from the antenna and the metal hat, not the actual transmision curve. This explains why the trace artifacts match the resonant size of the receive antenna.

    4. Anyone knowledgeable in RF/interference control knows that Aluminum naturally forms an oxide layer which forms an impedance at RF frequencies. Thus, the methods used in building the hats are per definition invalid for ensuring proper continuity at RF frequencies at the seams. Shielding requires continuity, otherwise a leak exists. These are not properly built tin foil hats.

    A few other issues to note:
    1. The equipment budget of $250k is highly exaggerated, even in 2005. Was this done to make the research look more qualified and important, or is this paranoia speaking?

    2. The explanations of the frequency allocations and their usage are oversimplified, check the official FCC frequency allocation chart at

    3. Most importantly: MIT gets a significant percentage of its research budget from government research contracts & labs. It makes one wonder if this is deliberate misinformation to make people believe tin foil hats do not work, so the government may exert its control freely.

    4. Note that guidelines for improved tin foil hat building were promised but not delivered upon. Government censorship??

    Seriously though: the government cannot even balance a check book, why would anyone think they can develop mind control capabilities?

  9. RichT says:

    I think this is the definitive authority on this topic

    though this guy seems to have considerable knowledge

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My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal

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