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Author Topic: Yet more KitchenAid stand mixer RFI  (Read 114 times)

Offline ChrisSmolinski

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Yet more KitchenAid stand mixer RFI
« on: September 06, 2019, 1115 UTC »
Broadband interference from the XYL's KitchenAid stand mixer. You can see when it turned on and off. This is her older, smaller mixer, the new larger mixer is even worse, I believe because it uses a variable speed DC motor drive.

Chris Smolinski
Westminster, MD
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Offline Kage

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Re: Yet more KitchenAid stand mixer RFI
« Reply #1 on: September 06, 2019, 1542 UTC »
Reminds me recently of a wallwort transformer. Had two 24v 500ma ones from different manufactures but looked identical on the outside with same plug. One I used plugged in would cause the nastiest RFI I have ever experienced. Thought it wasn't that big of a deal as I was using it on an audio device until I used it while transmitting and it caused my transmitter to hum like crazy. After pulling out hair and going nuts I remembered I had the other almost identical one and swapped them. Problem gone!
It makes me wonder sometimes how this shit is built. Sure I can open it up and investigate but there are times even when doing so I find myself stumped. It's like the chinese have some special ability to make the most noisy RFI devices feasible, and I couldn't generate that much RFI if I tried and I know how to build electronics that can!

Food mixers have a special place in my heart though. My mother had one when I was a kid and back when we had cable TV, yes cable.. not antenna. When she'd fire that thing up to mix stuff the TVs in the whole house would get visual lines going through them. I could hear the motor through the audio on the TV. Still no idea how such a simple device caused so much RFI. Kind of astounding to me now considering what I know about transmitters. All I can figure is that the thing was a giant spark gab transmitter motor somehow. Remember every weekend she'd make mashed potatoes and use it and... there goes The Simpsons for 10 minutes lol.
« Last Edit: September 06, 2019, 1547 UTC by Kage »
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Offline ChrisSmolinski

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Re: Yet more KitchenAid stand mixer RFI
« Reply #2 on: September 06, 2019, 1544 UTC »
Reminds me recently of a wallwort transformer. Had two 24v 500ma ones from different manufactures but looked identical on the outside with same plug. One I used plugged in would cause the nastiest RFI I have ever experienced. Thought it wasn't that big of a deal as I was using it on an audio device until I used it while transmitting and it caused my transmitter to hum like crazy. After pulling out hair and going nuts I remembered I had the other almost identical one and swapped them. Problem gone!
It makes me wonder sometimes how this shit is built. Sure I can open it up and investigate but there are times even when doing so I find myself stumped. It's like the chinese have some special ability to make the most noisy RFI devices feasible, and I couldn't generate that much RFI if I tried and I know how to build electronics that can!

I have posts where someone opens a device up and finds unpopulated RFI control components on the PCB. So they were included in samples built for compliance testing purposes, and maybe early production runs, and then removed to save 7 cents or whatever per unit.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline Kage

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Re: Yet more KitchenAid stand mixer RFI
« Reply #3 on: September 06, 2019, 1554 UTC »
<reply to: ChrisSmolinski>
I think that's a matter of muntzing. I hate to say it but I often do that to my own circuit too but only to the point to simplify things, not malfunction it. Think Apples Woz style muntzing. However these imported electronics take it to another extreme and don't care about our standards and that's how we end up with junk that causes RFI at best or a burnt down house at worst.
BTW I updated my last post since you replied. Sorry I have a tendency to do that thinking no one is online to read it.
« Last Edit: September 06, 2019, 1559 UTC by Kage »
I'm not saying aliens are in the radio, but aliens definitely are in the radio.
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