How To Fine Tune Wi-Fi Channels with the Help of iOS

If you have the AirPort Utility from Apple, you can enable the Wi-Fi Scanner to find out what channels your neighbors are using, then you can set your Wi-Fi router to avoid them.

Normally, the utility doesn't show the scanner.

To enable it, you need to go into your iPhone Settings, then scroll to the AirPort Utility:

Turn on the Wi-Fi Scanner:

Then switch back to the AirPort Utility, now there's a Wi-Fi Scan option:

Once you do a scan, you can see the other access points:

Tap on the info icon at the bottom, and you get a list of the devices grouped by channels:

Using this information, you can set your Wi-Fi router to avoid channels used by your neighbors. Often, routers automatically avoid crowded channels, but if they don't do this very well on their own, you can use this information to troubleshoot.