RE: Intermitten radio hits
There is an unfortunate problem in radio transmission called multipath. It means that the radio waves can arrive at your receiver from different directions caused by reflections of buildings,fences or even a small hill. Since the reflected wave has traveled a longer distance than the direct path it will be out of phase and can cancell the transmitted signal in a small area.
In the days before cable, and TV was usually on an antenna, an airplane flying over would cause the picture to flicker. The reflected wave from the airplane caused the signal to fade out at your antenna. That was multipath.
You can minimise the problem by having your receiver tuned to your transmitter. Then keep your hands off of the crystal.