[RFI] Swimming Pool Pump RFI

[Jim Brown]

On 6/25/2020 5:18 PM, Jim McCook wrote:
> No doubt it's a DC motor with a crummy Chinese switching power supply.

Or a variable speed controller for the motor. There's an app note on my 
website about building contest scores by killing RX noise. It ran 
several years ago in NCJ. k9yc.com

The first thing I would do is insist that the contractor and/mfr fix it. 
If you choose to try to fix it yourself, I'd start by winding 4-5 turns 
of every wire/cable connected to it through a #31 clamp-on. This means 
on the AC line side and on the motor side. And any control lines. These 
cables are transmitting antennas for the noise.

Also, make certain that the path for current to that motor is a 
transmission line -- in other words, forward and return current flow in 
very close proximity, which confines the field to a very narrow region 
between the wires. Minimum, "zip cord;" twisted pair is 30 dB better.

Also, I would be VERY, VERY cautious about working on this -- electrical 
safety can be a major factor. Several decades ago, a professional 
colleague was called in as an expert witness in a case where a preacher 
was electrocuted in the church's baptismal font while holding a 
microphone for the church's sound system (this was before the widespread 
use of wireless mics), and SOMETHING was not wired in conformance to 
electrical safety codes (the font or the sound system).

73, Jim K9YC