Re: Topband: Boradband noise on 160 meters tracked down to apartment complex

[Jim Brown <jim@audiosystemsgroup.com>]

On Sat,12/13/2014 5:35 PM, Don Kirk wrote:
> Now going back to the contractor that installed the equipment in an attempt
> to better understand the hardware in the unit
That smells like a Variable Speed Drive, the heart of which is a 
switching power supply that generates pulses in the 10 kHz range, the 
width of which are varied to control the speed of the motor. Lots to go 
wrong here -- switching power supply, square pulses of big current 
running a distance between the controller and the motor, often with 
supply and return conductors widely separated from each other, and with 
controller and motor widely separated, so the current flows in a large 
loop. Can you say train wreck?
73, Jim K9YC
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