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Why does every protocol use 2.4GHz? (sh.itjust.works)
submitted 3 weeks ago by to c/amateur_radio@lemmy.radio
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You guys are smart, and some quick googling got me nowhere. Why baby monitors, WiFi and Bluetooth ... All use same 2.4GHz frequency? I understand this is quite good frequency for home, indoor use and wall penetration etc...

But why is it exactly 2.4GHz? Why does WiFi not use 2.2GHz, bluetooth 3GHz and baby monitors 2.6GHz or 1.7GHz?

I have two hipothesis but I cannot validate them:

  1. For some reason this specific frequency is the only allowed for commercial use and other are used for military or other purposes?
  2. Interference would still happen if they would use mentioned frequencies since they are "close" together. If they use the same frequency, they can communicate and segment space more efficiently. But I do not know if this is actually happening.
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[–] 5 points 3 weeks ago

Since radio spectrum is shared globally because radio waves don't follow political boundaries, it's coordinated by a UN body called the ITU, the International Telecommunications Union.

There are a few frequency ranges set aside for so-called ISM (Industrial Science and Medical) use.

The 2.4 GHz band was set aside for such use and together with Wifi, Bluetooth and baby monitors, it's used for all manner of other things.

Since the range at low power is quite short, many devices can share the same frequency and not interfere with each other.

Here's some background.

https://en.wikipedia.org/wiki/ISM_radio_band

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