papajuliet wrote:
I can vaguely understand that a wifi connected device can pick up something from the ether but I've never worked out how the dictaphone did.
Tape recorder playback heads can often pick up AM signals nearby. In around 1966 our school CCF '12 Set' transmitted into an end-fed wire at around 5 MHz. Being ignorant, we didn't know how to tune the antenna, so instead of minimum dip on the 'wavemeter' we tuned it for maximum deflexion...
Causing very high SWR and lots of interference.
As a result, my guitar playing chum practising nearby would often hear us talking when he used his echo chamber - a somewhat primitive device which used a tape loop, one recording and several playback heads for the echo effect!