The Kensington WiFi Finder is a standalone gadget that lets you check for the presence of 802.11b wireless network hot spots (devices such as this are also called hot-spot sniffers). In our informal tests, unfortunately, it failed to perform reliably. You're better off with a site survey tool, such as the one built into theConfiguration Utility, or the Microsoft Zero Config utility built into Windows XP.
The WiFi Finder is roughly the size of four stacked credit cards; it fits nicely in a shirt pocket. It has a convenient, built-in keychain loop on one end. The top of the device includes a power button and three LEDs.
Turn on the WiFi Finder, and it begins scanning the immediate area. It takes several seconds to scan through the 11 available channels. The LEDs change colors depending on how "hot" or "cold" you are in your hunt for available access points. Yellow means cold; green means hot. If all three are green, you're smack-dab in the middle of a hot spot. If there is no signal present, one of the LEDs blinks to indicate that the WiFi Finder is still scanning. A few seconds after it detects a hot spot, the WiFi Finder resumes scanning for more signals. The unit turns itself off after two minutes to save battery power.
In our informal tests, unfortunately, the WiFi Finder failed to detect all hot spots consistently. It found the access points used in the NetNearU hot spots we tested, but it identified only some of the T-Mobile HotSpots we visited. The WiFi Finder also failed to hone in on two different access points (a Linksys WAP-11 and an Orinoco AP-2000) that our Wi-Fi adapter connected with easily. Kensington claims that many APs broadcast their SSID (Wi-Fi network name) too infrequently, causing the WiFi Finder to miss them. The WiFi Finder cannot detect access points that aren't broadcasting an SSID or access points based on the 802.11g standard, which could be a problem as more 802.11g hot spots come online. The unit also sometimes confused Bluetooth with Wi-Fi, indicating that there was a Wi-Fi signal when there wasn't one.