NetStumbler is designed to be useful to a number of different categories of users. A few of these categories are described below, along with some settings that might be useful.
Exposure to radio frequency radiation can be harmful. Read the manual that comes with your wireless equipment to see how far away you need to be from it in order to be safe. Use of an external antenna puts you at higher risk.
A corporate network administrator needs assurance that the wired LAN is not being exposed to unauthorized users. This can often happen when users set up their own wireless LANs for convenience. Such wireless LANs often have little or no security, which poses a risk to the entire LAN. The network administrator can use NetStumbler to detect the presence of these "rogue" wireless LANs.
The owner of a wireless LAN can use NetStumbler to verify that an area is well covered by a good quality signal. NetStumbler can also be used to see how far the coverage area extends beyond its intended boundary.
When installing or troubleshooting a wireless LAN, it is important to pick locations and channels in such a way that interference is minimized. A site survey typically includes finding out what existing items (microwave ovens, cordless phones, radio hams) are using the radio frequencies as the wireless LAN. A survey should done before installation of a new wireless LAN, and then subsequent surveys should be performed after installation. A full site survey requires special hardware such as an RF spectrum analyzer, but NetStumbler can also be used as part of a site survey.
Wardriving is the sport of detecting and/or locating wireless LANs. NetStumbler is a very popular tool for wardriving, because of its ease of use and GPS integration.
When setting up an antenna, NetStumbler can be used to assist with optimal antenna position and aim.