OK, so you know more about this than me. I'm sure my point is not lost on
others.
73,
--Alex KR1ST
On Jan 27, 2018, 5:11 PM, at 5:11 PM, Jim Brown <jim@audiosystemsgroup.com>
wrote:
>On 1/27/2018 11:11 AM, Alex wrote:
>> We purchased a LG washer (model WM3270CW) and dryer (model DLE3170W)
>> at the end of 2016 based on a Consumer Reports recommendation and
>> searching the net for *substantiated* reports of RFI problems (we
>> found none).
>
>Exactly what would you consider "substantiated?"
>
>> After installation I checked with a FT-817 around the appliances and
>> found no significant RFI from either.
>
>While we're all glad that you've found a good product that doesn't
>cause
>you problems, I would not consider your report "substantiated." Rather,
>
>I would like to see broadband waterfalls that cover a wide swath of
>frequency from an SDR connected to some sort of antenna close to the
>product and its wiring. Noise generated by electronic products that are
>
>not arcing tends to concentrated in frequency. There are broad "humps"
>of noise that repeat very 10 - 30 kHz and are unstable in frequency
>(generated by switch-mode power supplies and motor controllers), and
>there are steady (or pulsing) carriers (generated by microprocessor
>clocks and their circuitry. Noise from these products is often much
>stronger (or absent) in different frequency ranges. The 33V power
>supply
>that SteppIR shipped me was MONDO noisy between 17M and 10M (like 20dB
>over S9 on 12M into the 3-el on a 120 ft tower 200 ft away!). Noise was
>
>present on lower bands, but not nearly as bad.
>
>The most likely cause of RFI in a product that has a motor is a
>variable
>speed controller for it. Variable speed controllers are a strong and
>well known cause of RFI. They cause RFI when the motor is running, but
>are unlikely to do so when the machine is idling. Another likely cause
>is a switch mode power supply for on-board electronics.
>
>73, Jim K9YC
>
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