I have noticed that my iMac runs slowly sometimes when in the Communication mode. After a closer look I discovered that the iMac WIFI Modem goes off and connects with a unit in my neighborhood. I have an Apple Base-Station in the next room and cannot determine why this iMac doesn't stay connected there. I have looked for a method to secure it on one of my Base-Station Ports but have not been successful. What can I do to lock it manually?