What sound is heard from an audio device experiencing RF interference from a single sideband phone transmitter?
Why RF interference gets into an audio device when a nonlinear junction (a transistor input, a poorly bonded joint) rectifies the RF and recovers its envelope. An SSB signal has no carrier, so the recovered envelope is not a faithful copy of the modulation, and what comes out of the speaker is garbled, unintelligible speech that follows the rhythm of your voice.
Watch out Clearly audible speech is what you get from an AM signal, because the carrier travels with the sidebands and lets a simple rectifying junction demodulate it properly. On-and-off humming or clicking points to a keyed CW or pulsed signal, and a steady hum suggests a constant carrier such as FM.
SSB has no carrier to rectify against, so the audio comes out mangled: SSB in, scrambled speech out.