With a very few exceptions all Radio receivers are also, to a lesser extent, transmitters, the local oscillator, a fundamental part of a simple radio, will also radiate, to a greater or lesser extent depending on design, internal screening, and perhaps expence. I have seen quite expensive products that disgust the Radio Engineer in me ! Incidently this goes for anything with an oscillator in it, so computer clocks etc also qualify. That's why you don't use them.