Issue #21463: Garbled Radio Beacon doesn't stop transmitting
Inside the Cave interior cell near the crashed UFO, when you turn off the ham radio, the Garbled Radio Beacon continues to transmit and be available on your radio.
Actually I'd argue that even before that, killing the alien should cease the transmission. Other quests involving turning off ham radios, you must turn off the radio because it's an old message programmed on a loop, and the signal always says "this is a loop will repeat in 3 seconds" or whatever. In this case the message doesn't have that part, and I think it's logical that it's the alien sitting there as it does, making a live broadcast.