Many people set up their networks to hide their SSID, or Service Set Identifier. The SSID is the network's identifiable name. It is meant as a security measure, though users can easily scan for and find wireless networks with hidden SSIDs.
Download a program that will scan your network for hidden SSIDs. Many free utilities are capable of doing this, including inSSIDer, NetStumbler and or Kismet (see Resources). Only inSSIDer will show the hidden SSID. NetStumbler and Kismet will find networks with hidden SSIDs and display most of their information, but list the SSID as "Unknown."
Run the program and click the "Scan Now" or "Scan" button. The program will scan your wireless network for all signals coming from other networks, both hidden and broadcasting their SSIDs.
View the list of networks that appears when the scan concludes. All networks within range of yours will appear on the list. Compare the list with the list of wireless networks that your computer routinely picks up to determine which are hidden and which were already broadcasting their SSIDs.