Quote:
Originally Posted by Titan1a
I'm an AM DXer. I found that my CPAP would make noise running and a power brick for my son's laptop would make weird noises. Interference looks like lots of dashed lines in motion.
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This seems like typical motor commutation interference.
Zenith had a device they called "the growler" for testing analog TV sync circuits. It was a metal box with RF input and output ports that contained a vacuum cleaner motor coupled to the signal. It had a two stage speed control circuit that cyclicly varied the speed of the motor and the rate of change of the speed, thus creating interference streaks that ran through all possible phases with respect to vertical and horizontal sync. Eventually, integrated analog sync circuits could sync up when the signal was so much smaller than the noise that you could not make out what the picture content was.