As we mentioned, all WiFi detectors have interfaces that somehow inform you if a wireless signal is present. Apart from this basic function, however, all detectors are different. Manufacturers have come up with many methods for conveying the information to the user, and some of these gadgets are able to provide more information than others.
Many use LED lights, for instance. These typically light up in a scale fashion, where a single light indicates a weak signal, and more light up in sequence as the signal gets stronger. More advanced detectors use an LCD screen to display some useful information. Not only will it tell you the degree of signal strength, but perhaps also the SSID (Service Set Identifier), which is basically the name of the network. This would alert you to whether the wireless signal it's picking up is coming from your own home network or the neighbor's.
Detectors might also list the operating channel on which the network is working. This is helpful for reducing interference. It turns out that multiple networks working within the same proximity in the 2.4-GHz band can cause interference for each other. If you remember from the previous page, the 2.4-GHz band has 11 available channels in the United States. Interference can be reduced by spreading WiFi networks farther apart across the channel numbers. Thus, if your detector informs you that your neighbor's network is using channel 6, tune your router to channel 1 or 11.
When using WiFi detectors, remember that they run on batteries (usually AAA), so don't leave them on when you're not using them. Many include an indicator of battery that lets you know if it's in need of a replacement soon. Some actually have different settings that allow you to control the battery consumption or let you plug into your computer's USB port to charge [source: Dickey].
Another helpful feature is that some detectors can tell you if the signal is encrypted (secured). If it's encrypted, you'll need a password to use it. Unfortunately, some people who travel around looking for unencrypted wireless signals might use this feature against you. When you leave your network unencrypted, freeloaders might snoop into your Internet activities or perform illegal downloads (such as music sharing). Authorities looking for the perpetrators could trace these downloads to your network, and you could get wrapped up in legal frustrations even if they can't ultimately pin the fault on you. So, it's important to keep your wireless network secure and encrypted with password protection.
Overall, when you travel with a laptop, a WiFi detector can be one of the handiest travel gadgets to bring with you. You can even get a small keychain version to ensure you never leave home without it.