Definition - What does Wi-Fi Detector mean?
A Wi-Fi detector is a device used to locate wireless hotspots. Different types of these devices are sold under various brand names and set up differently. They may be hand-held, battery-operated units or units that connect to a laptop or other device through a standard USB port.
Techopedia explains Wi-Fi Detector
Wi-Fi detectors are used to identify frequencies between 2.5 GHz on the lower end of the spectrum to around 5 GHz. The mechanics around these devices have been standardized by the Institute of Electrical and Electronics Engineers (IEEE) under the 802.11 networking standard.
Based on 802.11, manufacturers connect an antenna calibrated for these types of frequencies to an interface that will give users information about nearby wireless hotspots. The information displayed on a Wi-Fi detector can include much of the same information that a user would get from the internal network connection center of a laptop or desktop computer, including basic signal strength, operating channel and service set identifier (SSID).