There is a really helpful article over on Macinstruct about the weird feature in Airport called “interference robustness.” I’ve always wondered what that did, and more importantly, if it does something good, why is it off by default?

The answers are here:

Using Interference Robustness will essentially slow down your wireless connection. As discussed above, if you’re looking for speed, you send a high frequency of large packets. If you’re looking to battle interference you send smaller packets at a lower frequency. So your connection will be slow but strong.

Another important thing that this article notes is that “Use Interference Robustness” only applies to Apple’s AirPort networks:

It’s also important to understand that if you run a Mac and use a Linksys, Netgear, Belkin or one of the many other options one has, checking the “Use Interference Robustness” option will not work. Interference Robustness is specific to Macs connected to Apple’s AirPort Express and Airport Extreme.

• What is Interference Robustness?