The principle of cell phone signal jammer. However, the frequency of electromagnetic waves ranges from a few Hz to several hundreds of GHz, and each segment can be used as a communication signal. Will there be some special frequency bands used in the examination room? In fact, radio communication tools with dedicated frequency bands "came into being" under such circumstances. The operating frequency bands of these devices are selected outside the frequency bands covered by cell phone jammer , and Selective Cell Phone Blocker has no effect on them. For this special radio communication tool, the examination room is specially equipped with a monitoring vehicle equipped with a radio monitor for real-time monitoring of radio wave signals from unknown sources.
Can schools install Selective Cell Phone Blocker ? The Qian News reporter consulted Cao Dan, director of the Hangzhou Radio Administration Bureau, on this issue. Director Cao made it clear: "It's impossible." Except for very small radio stations, no approval is required. All other radio stations require approval because they involve the use of frequencies. "But so far, we haven't approved any of them in Hangzhou," explained Director Cao. Schools may use cell phone jammers. "Qianbao reporter found at the scene that Yinhu Experimental School is nearly one kilometer away from Shijiayuan. Is the coverage of mobile phone jammers so wide?
