A transmitting antennae for radio wave of 5 wavelengths is located on land 190 above the edge of the ocean. An airplane flying just above the surface of the ocean 20,000 meters away from the antennae cannot receive signals and thus does not reflect signals back to the transmitting signal.
a) Describe why this happens (I think this is because of destructive interference caused with multipath of incoming signal as it bounces of the ocean?)
b) At certain altitudes the plane will reflect exceptionally strong echoes compute these altitudes.