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Aluminum foil can increase the range and security of your Wi-Fi router

By Cal Jeffrey ยท 12 replies
Nov 8, 2017
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  1. If you are old enough, you might remember your dad balling up tinfoil on the rabbit ears to bring in channel four a little bit clearer. Results of this little trick were negligible at best and usually required multiple applications of foil until it looked like the TV was ready to go bowling. Now it appears that your dad may have been onto something.

    Researchers at Dartmouth University have discovered that not only will aluminum foil increase the range, reception and speed of WiFi signals, it can also shape them in ways that make your router more secure. However, the method described in their paper differs considerably from your dad’s.

    Instead of putting foil directly on the router’s antenna, they instead used a 3D-printed shape wrapped in aluminum and placed it around or behind the antenna.

    The 3D reflector can be custom-formed to fit any router design to shape its signal to precise specifications. For example, you can print one that blocks the signal from going out the window but increases the range, speed and reliability within a specific room in the house. Best of all, it’s cheap and effective.

    “With a simple investment of about $35 and specifying coverage requirements, a wireless reflector can be custom-built to outperform antennae that cost thousands of dollars,” Dartmouth professor and project lead Xia Zhou told EurekaAlert.

    To create the antenna aides, Zhou and his colleagues developed a software program called WiPrint. By inputting the desired signal shape requirements, the app creates a 3D-printable image. Once printed, you only need to wrap it up in foil.

    They have not released the software yet and have not announced a date when it will be available (if at all). However, the team is presenting its research and the software at ACM's BuildSys 2017 in Delft, Netherlands on November 8.

    Permalink to story.

  2. jobeard

    jobeard TS Ambassador Posts: 12,791   +1,508

    Take (2) 8x11 cardboard backings and cover with Al foil. Place together at right-angles and experiment with the distance to the router antennas.

    This forms a directional reflector straight between the two antennae away from the reflector and at the right distance, the waves interact in a 3rd harmonic, additive fashion. This is '30-40's short wave radio technology :grin:

    A MIMO router with both IN & OUT antennas will not do well with this.
    Last edited: Nov 8, 2017
    Reehahs likes this.
  3. How is this news? I remember doing this with my Linksys 802.11b router 15y ago.
    Reehahs and Jeff Re like this.
  4. Uncle Al

    Uncle Al TS Evangelist Posts: 5,249   +3,661

    And let's not forget that it's great for blocking those pesky radio waves from Mars that my neighbor is constantly raving about while he covers his latest football helmet with Reynolds best!
  5. EClyde

    EClyde TS Evangelist Posts: 1,803   +664

    I never heard of it before and it's cool
  6. Kenrick

    Kenrick TS Evangelist Posts: 630   +403

    You are right. I remember an article to a linksys wrt about this before. Just make sure there are no plants along that direction beam or it will slowly die.
  7. fktech

    fktech TS Maniac Posts: 522   +136

    Back scatter still escapes. Marginally blocks signal and questionable direction improvements
    jobeard likes this.
  8. Cal Jeffrey

    Cal Jeffrey TS Evangelist Topic Starter Posts: 1,698   +410

    Researchers found that the reflectors can decrease strength by up to 10 dB where the signal is not wanted and increase strength by 6 dB where it is desired.
  9. GabeNeo

    GabeNeo TS Rookie

    I put a layer of Al foil on my Kodak trucker hat and I feel better already...
  10. Potato Judge

    Potato Judge TS Booster Posts: 161   +73

    Cool. Added to my DIY projects.
  11. lazer

    lazer TS Addict Posts: 235   +56

    I figured if aluminum foil can help to focus the wifi beams, if I cover the wifi modem router with aluminum foil it will cause a decrease in the spread of the wifi beams. So I covered my wifi modem router with the foil and see if it decreased the reception on my laptop.

    So I covered my wifi modem router and checked my laptop to see if there was any decrease in the bars; there was NO (zero) decrease in reception.

    So if the aluminum foil can not block the wifi beams, it certainly can not reflect them to increase the distance.

    Easy for you to try. See if I was correct. The aluminum foil is a joke/scam.....
  12. Your knowledge of electromagnetism is lacking. Transmission is not a binary function; yes/no. Frequencies transmit through a conducter based on frequency, conductivity, and thickness. Skin depth.

    It's like covering a light bulb with clingfilm and claiming its a bad insulator. For example, reflection depends on polarization, the angle which the light hits the material, the colour of the light, and refractive index of the material. Life is not that simple.

    Put a laser beam of the right colour, at the right angle (Brewster), and you will have zero transmission on cling film.
  13. fktech

    fktech TS Maniac Posts: 522   +136

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