This calculator calculates the maximum field strength that a dipole antenna could produce at 3M assuming 100% antenna efficiency.
Equations:
\( \text{Power Density (PD)} = \frac{\text{Power}}{4 \pi r^2} \)
\( \text{Volts/meter} = \sqrt{\text{PD} \cdot 377} = \sqrt{\frac{377 \cdot \text{Power}}{4 \pi r^2}} \)
The 377 factor is the resistance of free space in ohms.
Dipole gain in dB compared to an isotropic antenna is 2.15dB, so the gain is 1.281.
Thus, the maximum field strength for a dipole is:
\( 1.281 \cdot \sqrt{\frac{377 \cdot \text{Power}}{36 \pi}} \)