A transmitter for an FM radio station (WICB) in Ithaca, NY operates at 91.7 MHz with a power of 4.1kW. The transmitter is mounted on a tower 35m from the ground. Assume that the transmitter radiates isotropically (equally in all directions).
a) Calculate the time-average power density that a person standing at the foot the antenna tower will experience.
b) The IEEE safety limit for radiation exposure at this frequency is 0.2 mW/cm^2. Use this fact and your answer in part(a) to advise the local college students if it is a good idea to have a keg party at the base of the radio tower.
c) Supposedly people can pick up the WICB signal all the way at the shores of Lake Ontario 72 miles away. Calculate the average power density at this distance and the corresponding peak electric field amplitude.