Transmit Power (W):
Antenna gain (dBd):

E = sqrt (30 * Pt) / D; D = sqrt (30 * Pt) / E
E = Electric Field in V/m, Pt = Transmitter Power in watts, and D = Distance from Transmitter to device in meters.
EN 50082-1 & EN 50082-2: Equipment must work undisturbed in a RF field between 80 to 1000 MHz, with 80% AM (1 kHz).
EN 50082-1: For residential, commercial and light industry 3 V/m stress level is used.
EN 50082-2: For heavy industry environment 10 V/m stress level is used, except for the ITU broadcast frequency bands: 87 MHz - 108 MHz, 174 MHz - 230 MHz, and 470 MHz - 790 MHz where the level shall be 3 V/m.