Consider two antennas separated by a distance of 168 m which are each generating radio waves with a frequency of 7.4 MHz in phase with each other. The two antennas are located with one directly west of the other one. What are the two farthest points directly north of one of the antenna where there will be destructive interference, so that a radio receiver placed at that poit would not pick up any signal? (Hint: Consider the difference in path length for the two signals that will give destructive interference.)

Farthest y? m
Next farthest y? m

Question

Consider two antennas separated by a distance of 168 m which are each generating radio waves with a frequency of 7.4 MHz in phase with each other. The two antennas are located with one directly west of the other one. What are the two farthest points directly north of one of the antenna where there will be destructive interference, so that a radio receiver placed at that poit would not pick up any signal? (Hint: Consider the difference in path length for the two signals that will give destructive interference.)

Farthest y?	  m
Next farthest y?	  m

radar · Answer

The difference would need to be 1/2 wavelength.  Also the field strength of the two RF signals would have to be equal as well as out of phase.  If we were to assume that the two antennas had the same power level, and that there is to be a 180 degree difference at the location, then one signal will have traveled a different distance and would not be totally destructiver, in other words a receiver would more than likely pick up some signal.