The air was charged by the activated electromagnetic field surrounding the compound.
We intercepted some emergency transmissions but couldn't get everything because of the electromagnetic field.
Electromagnetic voltmeters consist of a coil of fine wire connected to the terminals of the instrument, and the current produced in that wire by a difference of potential between the terminals creates a magnetic field proportional at any point to the strength of the current.
Function of receive antenna is extraction energy from electromagnetic field.
Electromagnetic voltmeters may therefore be thermal, electromagnetic or electrodynamic. As a rule, electromagnetic voltmeters are only suitable for the measurement of relatively small potentials - o to 200 or 300 volts.