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Comment by dhdc | Hacker News Reader

5GHz actually has worse penetration and stronger attenuation over distance than 2.4GHz. Succesfully blocking 5GHz does not imply the same for 2.4GHz.

However I do agree that it's probably still gonna work because the faraday cages on microwaves are always overkill (even the cheap ones).

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> 5GHz actually has worse penetration and stronger attenuation over distance than 2.4GHz. Succesfully blocking 5GHz does not imply the same for 2.4GHz.

In this case it could be the opposite: faraday cages only work for blocking wavelengths that are longer than the wavelength that it's designed for (presumably 2.4ghz). Therefore it could be blocking 2.4ghz but letting 5ghz waves through because it's too small to contain.

As long as the hole size in the faraday cage is much smaller than the wavelength, it will work. The front mesh of a microwave typically has openings on the order of millimeters, which is still good enough for 5GHz.

a cheap consumer RF meter detects "high" levels of RF from 5+ feet away, at least on the 4 or 5 random units I've tried. So the faraday cage doesn't seem to be doing its job in full.

A "high" from a random RF meter doesn't mean anything. Give me numbers in dBm/MHz.

RF leaks can be pretty directional. So simple tests like this phone test or waving a power meter around aren't terribly sensitive. (But pay attention if you get a test failure!)

There really isn't any substitute for a proper EMC chamber.

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