# Why can a cellphone ring inside a microwave?

I placed my cellphone inside my microwave. This notwithstanding, my step mother was able to call me, again. Is it a normal thing or I need to change of microwave ? I believed faraday cage of a microwave could stop these wavelength (900-1800 Mhz)...

By the way, It is an old microwave (bought fifteen years ago). Its frequency must be around 2.4 Ghz but I lost the manual, the door was well closed, I verified.

• was the door left slightly open? – hyportnex Feb 20 '18 at 14:58
• that right, yes it is around theses frenquency, I tought – snoob dogg Feb 20 '18 at 15:00
• @hyportnex no! I closed it well – snoob dogg Feb 20 '18 at 15:02
• @KyleKanos to avoid receiving calls from my step mother (as I said) -_- – snoob dogg Feb 20 '18 at 21:59
• @KyleKanos sometimes you receive so much calls from your step mother that you act weirdly to avoid them – snoob dogg Feb 20 '18 at 22:01

With a cell phone, the radiation is in the same frequency range, but you’re dealing with a dramatically more sophisticated beast. Cell phones have variable amplifiers, error-correcting codes, and other engineering tricks that can handle a huge dynamic range of signal strengths, ranging from the enormous signal you’d get if you were standing under a cell tower all the way to the minuscule signal you’d get out in the wilderness. Remember, the power of the radiated signal from a tower decreases as $1/r^2$, so your phone has to be able to measure small signals to be useful. If you have a decent cell signal at your house to begin with, it doesn’t matter if you put the phone in a cage that drops the signal by a factor of 1000. That’s the difference between being away from a cell tower by 50 meters versus a mile: the phone can handle it.