A mobile phone is configured to employ existing antennae or other exiting input electronics to receive electromagnetic waves, for detection of energy magnitudes. The mobile phone has wireless receiver electronics to receive, through the antennae, communication signals in a plurality of different communication bands that correspond to the plurality of different frequency ranges. Energy levels of electromagnetic waves received through the plurality of antennae are detected. A record is made of energy levels in the plurality of different frequency ranges. An alarm is provided upon a detected energy level crossing a predefined threshold value.