Power Density at Target Position
 Equation:       Pd =     (Pp x G) / (4 x pi x r2)
 Where:
 Pp  = peak power
 Pd  = power density
 G    = antenna  gain
 r     = range
   
 Example:     Pp= 0.001 Watt
G    = 31.6 (15 dB)
r    = 200 m
            Pp       G              pi       r
PD = (0.001 x 31.6) / (4 x pi x 2002)  =      1.22-7 Watt  or  -69 dBW/m2