Canary’s hot spot finder is the best of the several stand-alone Wi-Fi detectors that I’ve tried — three of which I’ve gone so far as to purchase. The Canary uses AAA batteries, rather than the button cells that some detectors do (harder to replace in a pinch); consequently it’s not quite as svelte as some, but the extra goodies are worth the chubbier, still-palmable housing. Canary’s unit scrolls across its 12-character LCD display the name, channel and signal strength (4 bars is the highest) of the networks it finds, which makes it truly useful for checking where your own access point’s signal reaches.
It also displays each network’s encryption status. (Encryption isn’t the only means of preventing access, though, so an “open” network may not be open to you if your MAC isn’t on the “approved” list.) Bonus: Canary’s is the most sensitive of the detectors I’ve tried; my older Kensington sometimes didn’t want to light up unless it was nearly on top of an access point. I’ve used the Canary to find the best parking spot when working from Flying J truckstops around the country, which sure beats walking around with an open laptop playing “find the antenna.”
[*The HS 10 has since been replaced by the HS20. If you have any experience and can report positively or negatively, please let us know in the comments below or via the submit page.]