What would cause a broadcast AM or FM radio to receive an amateur radio transmission unintentionally?

When a consumer AM or FM radio unintentionally receives an amateur radio signal, the fault often lies with the consumer receiver itself, not the amateur transmitter. Consumer receivers are sometimes built with inadequate filtering, meaning they cannot sufficiently reject strong nearby RF signals that are outside their intended frequency band. This phenomenon is known as fundamental overload. The distractors point to issues with the amateur transmitter, such as microphone gain, audio amplifier overload, or low FM deviation. While transmitter issues can cause poor audio or splatter on adjacent amateur frequencies, they do not cause a completely different band to pick up the signal. If your transmitter is operating normally but interfering with nearby consumer electronics, it is usually a receiver filtering issue.