• Etterra@discuss.online
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    1 hour ago

    Remember when some jokers started selling Faraday cages for Wi-Fi routers on Amazon, claiming that it would protect the user from wireless signals?

  • 𞋴𝛂𝛋𝛆@lemmy.world
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    11 hours ago

    This is a 2.4 GHz directional WiFi antenna. Only the back element is connected to the transceiver. All of the other elements are there to focus the signal. Anything metallic within a few feet of an antenna will have a substantial effect on the signal. Think of it as light, because it is, only transparency of materials is a bit weird. The biggest issues will come from metallic materials that are earth grounded and anything with a wire length that is close to the wavelength of the radio light or below, especially around half and a quarter of the wavelength. That pictured wire pitch is spaced very close to the approximate 2.4 GHz wave length. For example most antenna are an insulated trace on a circuit board that is insulated with ground up to a point and then there is a small circuit element that stops the ground and the actual antenna trace continues for the respective light wavelength to transmit or receive. All an antenna is here is an exposed length of single conductor wire.

    • JasonDJ@lemmy.zip
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      9 hours ago

      Wifi is a fickle beast, though you may be right.

      The elements of the cage will probably interfere, but won’t straight up block the signal. To be an effective faraday cage, holes in the material must be no bigger than 1/10th the wavelength.

      2.4GHz wifi has a wavelength of 12cm, and 5GHz is about 5cm…so holes in the cage should be no bigger than 1.2cm for 2.4GHz, or 0.5cm for 5GHz.

      I may expect some signal reflection and likely a high noise floor as a result to being so close to a hunk of metal. That’ll cause some problems.

      Problem #1 is this AP is oriented vertically on a wall. The antennas in these models are designed to be parallel to the floor, and usually not much higher than 15ft.

        • zqps@sh.itjust.works
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          5 hours ago

          Newer standards are substantially shorter at 5GHz and 6GHz, but this comes at the cost of significantly worse signal penetration through walls.

    • deegeese@sopuli.xyz
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      11 hours ago

      The bar spacing is smaller than 2.4GHz radio waves. It absolutely will affect signal. Should have used a plastic cage.

      • Grostleton@lemm.ee
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        11 hours ago

        Faraday cages cannot block stable or slowly varying magnetic fields, such as the Earth’s magnetic field (a compass will still work inside one). To a large degree, however, they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation

        I’m certainly no expert, but something tells me the cage in OP’s pic doesn’t fit the criteria to act as a faraday cage.

        • zout@fedia.io
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          11 hours ago

          It will not act as a Faraday cage, the holes need to smaller for that, about 1 cm max. However, wifi signals do get disturbed by a cage like this due to the low power of these signals.

        • deegeese@sopuli.xyz
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          11 hours ago

          The mesh is not dense enough to be a true Faraday cage for 2.4GHz, but is dense enough to hurt signal strength.

          • socsa@piefed.social
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            6 hours ago

            Probably not for a MIMO AP. The whole idea is that you solve the equations to optimize in the presence of multipath. It’s legit wizard shit but it’s the reason why your cell phone works in a parking garage, because the optimal channel is bouncing off the ventilation shaft. For any reasonably modern AP, it should work the same way. This might hurt a bit but not that much.

            • deegeese@sopuli.xyz
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              4 hours ago

              MIMO will solve lensing issues but not internal reflection or absorbance.

              So like OP says, it’s a signal strength issue.

        • Snot Flickerman@lemmy.blahaj.zone
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          11 hours ago

          It says WiFi is “slow” not “off.”

          I have definitely personally experienced WiFi instability with metals in between the WiFi and a PC.

          Looks like possibly enough to make it drop a bunch of packets to me at least.