Back in the late 50's through the 60's, diathermy machines used frequencies around 27.255 MHz. If you were within range, you heard tones and occasional howls.
OK, so all those "good buddies" may not have been crazy! Thanks for sharing.
You also had all the super cheap remote controlled planes, trains and automobiles...... Well, maybe not trains??? In the 70s and 80s.
The best ones for amusing yourself at the neighbor kids expense where the ones with a simple button. Push the button, it backs up and makes a left. A carrier anywhere in the 11 meter band would send the car into reverse. Modulating said carrier and it would start, stop, stutter, etc. Usually you could get the kid to yell, scream and curse. Great amusement.
The better ones had modulated tones that would signify forward, backwards and direction change in the early days. Various whistling was fun.
Also, a carrier on 12 or 14 would usually wipe anything out anyway, since they usually bootlegged on the CB freq instead of the actual RC designated channels. Some of the cheapest units didn't even have a crusted, just an lc oscillator.
I can still remember a blonde hired neighbor kid throwing his remote and stomping off into his house! Lol
--Shane
KD6VXI