Making WiFi fast

Making WiFi fast

If you're going to make comments like that, please make sure you actually *know* the physics. The relevant equation in this case, the Friis path loss equation, has a lambda squared on the top, or if you prefer f squared on the bottom. So yes, path loss is significantly lower at lower frequencies; this is the reason that satellites use the lower of a pair of frequencies to transmit (because they are power-constrained); likewise frequency-division duplex phones will use the lower frequency channel for the uplink (again, power-constrained). This is also the best-case scenario; usually the path loss exponent is higher than 2 due to multipath fading (due to reflections).

Here's a graph if you aren't convinced.

5 GHz is severely attenuated by relatively mild obstructions (such as gyprock/drywall or timber) that 2.4 penetrates very easily. If you have concrete or brick walls, you'll want an AP in every room.

The main benefits of 5 GHz are that you have a lot more non-overlapping channels, so it is easier to avoid interference - it is also good if you have a lot of users to support and want to have a LOT of short-range APs.