A microwave antenna has a power output of 5700 watts and a gain of 5000. Calculate the required decibels of attenuation for a shield that would reduce the exposure from this antenna to a value equal to the allowable power density (OSHA RPG ) at a distance of 69.8 feet (2128 cm) from the antenna. Assume this point is in the far field. [note: dB attenuation = 10 log (W0 /W)]
