Apple AirPort Time Capsule 802.11n (3rd Generation) - Manual (Page 31)

Chapter 3 Tips and Troubleshooting 31
 The original coaxial cable that came with certain types of satellite dishes. Contact the
device manufacturer and obtain newer cables.
 Certain electrical devices such as power lines, electrical railroad tracks, and power
stations
 Cordless telephones that operate in the 2.4 or 5 GHz range. If you have problems
with your phone or AirPort communication, change the channel your base station or
Time Capsule uses, or change the channel your phone uses.
 Nearby base stations using adjacent channels. For example, if base station A is set to
channel 1, base station B should be set to channel 6 or 11.