I've heard a legend of a small town broadcast engineer that bought up all the local fcc licensing and was transmitting low power frequencies with no content. Years later, I got curious about radio, signal propagation, wavelengths and the such. It's clear that harmonic frequencies can easily interfere with the main ones and, to top it off, can do so at very low power. Just haven't clued into what that legendary engineer was blocking but there's some pretty wild theories...