The wifi signal jammer will generate heat when working, so cooling fans and heat sinks need to be installed to ensure that the machine does not burn out when working. But not every shield will produce particularly loud noise when turned on, because the fans used are basically silent. Only those shielders with particularly high power use relatively large fans. Even silent fans will still make noise. Therefore, human ears can clearly feel it. I don’t know how much power you bought. If it is a low-power jammer, there should be something wrong with the equipment.
The shielder will generate a lot of heat when it is working. In order to make the shielder work stably for a long time, a cooling fan is added to the machine. The fan makes a sound when it enters the door, so you can hear some sounds when the shielder is working. .
The more powerful the shielder is, the louder the sound is. Due to the high heat dissipation requirements, the fan used is also larger, and the sound is also louder at this time.
Don't blindly choose a high-power jammer. For a classroom, choosing a 2W transmit power jammer is enough to achieve the shielding effect.
After use, be sure to turn off the shield in time to avoid continued radiation.
Be sure to choose a signal blocker produced by regular manufacturers. Jammers produced by informal manufacturers often deliberately increase the transmission power in order to pursue better shielding effects.