Airport disconnects for a couple seconds and reconnects. How to stop?

Often, several times a day my Airport connection will disconnect for a couple seconds and, then, automatically reconnect. The Airport icon at the menu along the top of the screen will have the length of time connected to its right. The icon will move to the right as the time disappears. After a couple seconds, it reconnects and the timer reappears, usually picking right up where it was before rather than restarting at zero. This would be nothing more than an occasional pause while online except that, sometimes it causes my iTunes library, which I have designated as a folder on an external hard drive,to default to the original iTunes folder under Music on the hard drive. I, then, have to change the library back which can take ten minutes each time because I have a very large music collection. Is there any way to stop my connection from doing this? If not, is there a way to stop my iTunes library from defaulting back to its original location? Storing the music on the computer is not an option; like I said, I have a very large collection.

Thank you.