[sp332]

Luminous efficacy depends on wavelength, with the eye being most sensitive to 555nm (green) light at 683 lumens/Watt. Most wifi setups max out at 1W (I think?), so if the eye were as sensitive to wifi signals as to green light, we could get 683 lumens which is about the same as a 60W incandescent bulb.

[lcedp]

And?

[sp332]

Oh, so if we're trying to imagine how bright a wifi router's "light output" would look if we could see it, we can just imagine a 60W (monchromatic, say green) lightbulb. Of course the light would pass through walls more easily which is a bit unusual :) But for attenuation over free space, I think the analogy to a 60W light bulb is very useful.