Re:Apple Introduces Oceanic+
by jitl on Monday November 28, 2022 @11:15AM
(#33775426)
Bluetooth doesn’t work underwater. Water loves to absorb 2.4ghz signals. I dive with both my iPhone and Apple Watch Ultra and they can’t communicate underwater unless they’re actually touching.
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Oh that's interesting. Made me go digging. It turns out those air integration wireless tank sensors use very low frequencies, 38kHz. MH8A is the relevant FCC ID.
Curiously, 2.4ghz light corresponds to microwaves which is actually long wavelength low energy light. If you have a video stream on while the microwave oven is turned on you'll notice large enough interference to disconnect your stream.
The fact that water absorbs 2.4ghz light is what enables microwave ovens to heat water in the first place. So while it's an inconvenient property during dives, it's very convenient in the kitchen.