Radio antenna

I spent years working in avionics with signaling systems. The the way an antenna works is based on the frequency of the signals being transmitted and the associated wavelengths. You need a full half wave and the antenna itself is only 1/4 with the other quarter developed from the ground plane it is attached to, just the way it works. The fiberglass hoods on T/A’s and AAR’s does not provide an effective ground plane thus the antenna is located in the rear for proper function. Hope this is helpful and good luck. Note that the intensity of the spark signal can still mess up AM radio signals and often will require addition of a filter (capacitor) in the power source for proper operation.