Washing Machine RFI -- A Tidal Wave?

Washing Machine RFI -- A Tidal Wave?

My wife and I have a Whirlpool Duet washer and dryer. The RF noise that the washer makes is terrible. I used my Elecraft KX1 and a clip lead antenna for finding where the noise was strongest. It all comes from the front control panel, which is plastic. Little comes from the power cord. I also found tremendous noise used on AM and FM broadcast radios in the house.

I posted a message to an RFI mailing list, and found a few other people with similar problems, using Gibson and Maytag Neptune brands.

The Gibson washer was quieted by an AC line filter, but nothing has helped the Whirlpool Duet or Maytag Neptune. It appears that the noise comes from the control panel and the variable-frequency AC motor circuits.

I asked Whirlpool for their Part 15 certification, and found out by reading the regulations that they don't have to have a certification number for computer and control circuits in appliances.

While these front-loading, computer-controlled washing machines are on the higher end of the price range right now, it is my belief that this new generation of washers is going to produce noise on a tremendous scale as consumers begin to demand them and prices come down. I believe that the manufacturers are exploiting a loophole in Part 15, and one that isn't even mentioned in the ARRL's Part 15 page. See Part 15.103, "Exempted Devices":

Sec. 15.103 Exempted devices.

The following devices are subject only to the general conditions of operation in Sec. Sec. 15.5 and 15.29 and are exempt from the specific technical standards and other requirements contained in this part. The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected. Although not mandatory, it is strongly recommended that the manufacturer of an exempted device endeavor to have the device meet the specific technical standards in this part.

(d) A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.

So, in summary, I believe that we are headed for an onslaught of RFI from washing machines.

Here are the details for my Whirlpool Duet.

• Here is the sound on 20m in one frequency, with the washer spinning and stopping. This is just one of the noises it makes, and not the worst (see the specifics below).
• When it's off, there's still broadband noise coming from the switching power supply. It seems to be radiated through the front panel. It also makes discrete noise that I can hear 4 feet away on an FM broadcast radio, even when the unit is off.
• When it's on and the motor is running, it makes a tremendous racket, about every 17 KHz, with bands of noise. This noise too seems to radiate most strongly from the front panel.
• There is to be some broad noise during operation, but the strongest most of the noise is concentrated in at intervals. One set of noises repeats as follows, during spinning and some times filling: 14.005 14.022 14.03750 14.053 14.070 14.085 14.10250 14.11750 14.13250 14.18250 14.19750. Another weird, different noise was at 7.57760

Whirlpool has sent me a new motor and control unit to install and see if the problem is particular to my unit, but they said there were no hardware changes in the parts at all. Unfortunately I've been unable to this because the washer is now in storage during construction work, and I'm trying to decide whether to get a new washer.

Spectrum Images

The images below are waterfall images from my PSK program connected to two different receivers. Note that the band starts out quiet, with weak PSK signals present, and then gets a broad noise, followed by discrete bands of "carriers" at multiple frequencies, which then shift and move, and finally stop.

K2 Images

• This image shows operation just before the washer started. 7.030-k2-clear:
  
• This shows the noise of the washer starting, fairly quiet before any mechanical action. 7.030-k2-washer-starting:
  
• This shows the washer rotating, on a different frequency that is subject to noise. It's fairly broad at this point. 14.070-k2-washer-start-rotating:
  
• This is a weird noise (to the right of the blue lines). To the left is foreign SSB transmissions. 7.05775-817-washer-spinning3:
  
• This shows that the noise stops when the rotating stops; notice how the weak PSK signal becomes visible around 1150Hz offset. 14.070-k2-washer-stop-rotating:
  

FT817 Images

I switched to my FT-817 for general-coverage operations.

• Here's a baseline with the washer on but not spinning. You can see that the broad noise is present, but there is no discrete noise. 14.070-817-washer-on:
  
• The motor spun at different speeds during this period and you can see the see the lines vary. 14.070-817-washer-spinning:
  
• Again, when the washer stops, weak PSK signals can be seen. 14.070-817-washer-still:
  
• When the water pump turns on, broad noise is seen. 14.070.817-washer-pump:
  
• Broad noise from washer spinning at a slightly different frequency, 2KHz up. 14.072-817-washer-spinning:
  
• But it gets worse at the same frequency with spinning. 14.072-817-washer-spinning2:
  
• Again visible 7.75KHz up but a little quieter. 14.0775-817-washer-spinning:
  
• The pump made some really weird noises on 40 meters. 7.045-817-washer-pump:
  
• More weird pump noises on 40 meters. 7.045-817-washer-pump2:
  
• Different noises on 7.060 7.060-817-washer-noise:
  
• The pump again on 7.060 7.060-817-washer-pump:
  
• And a weird spinning whirring that changes frequency. 7.060-817-washer-weird2:
  

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