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Author Topic: Dishwasher RFI  (Read 257 times)

AF5CC

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Dishwasher RFI
« on: May 22, 2021, 12:23:32 PM »

I have been having some noise on 2 meters, making it harder to hear the satellites in certain directions, and I have finally traced it down to the new dishwasher we bought a few months ago. It is a Frigidaire Galley Model number FGID2468UF1A (in case you want to avoid this model).   

I tried wrapping the power cord, which is a flat, about an inch wide 3 pronged AC cord through a rectangle torrid I have on hand that would split in half for easier access.  I could fit 2 turns of the cord through it.  That didn't make a difference.  I have a larger ring torrid but the plug on the cord is a little too large to fit through it.  I am sure I could get a larger diameter torrid if I thought it would work.

So, what is the best plan of attack on the RFI-other than just unplugging the dishwasher when I am not using it.  I can probably only get 2 or 3 turns max through a ring torrid due to the length of the cord.  Is this the best solution for RFI, or what other methods can I try?

73 John AF5CC
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K1KP

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Re: Dishwasher RFI
« Reply #1 on: May 22, 2021, 12:39:58 PM »

I had this problem with a new dishwasher purchased about 6 years ago. The RFI sounded like <GET THIS> dripping water!

I added several turns of the line cord through 2.4" mix31 core. That takes care of common mode, but wasn't enough. I bought a line filter for it:

https://smile.amazon.com/gp/product/B0000510Z9/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

This did the trick for differential mode noise.

-Tony, K1KP
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AF5CC

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Re: Dishwasher RFI
« Reply #2 on: May 22, 2021, 12:59:10 PM »

Just bought the line filter for it.  Supposed to be here tomorrow. If nothing else, it will make it easier to reach in and turn the unit off and on using the switch on the filter, better than having to unplug and plug in the dishwasher all of the time.

Thanks for the advice!  My RFI just sounds like static.

73 John AF5CC
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W9IQ

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Re: Dishwasher RFI
« Reply #3 on: May 22, 2021, 01:38:50 PM »

John,

Please report back here how it worked for you.

- Glenn W9IQ
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

AF5CC

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Re: Dishwasher RFI
« Reply #4 on: May 25, 2021, 09:54:49 PM »

The Tripp Lite filter did nothing for it.  I am sending it back to Amazon for a refund.  I bought a power strip from Wal-mart instead, and am using it to turn the power on to the dishwasher when I need to run it. The rest of the time I will turn the power off to it.  That is my solution for now.  Will keep trying other things as well.

Unfortunately dishwasher are except from Part 15 rules.

73 John AF5CC
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N0GV

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Re: Dishwasher RFI
« Reply #5 on: May 26, 2021, 02:09:25 PM »

Hi John,

Is this noise spread spectrum or is it repeated periodically? Spread (wide) spectrum is usually some sort of discharge noise. If it is periodic then it is likely from the control unit switching power supply. Filtering that may help, a line filter is unlikely to be useful. Replacing the control unit or modifying it to a filtered configuration might be useful.

Grover
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WB4SPT

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Re: Dishwasher RFI
« Reply #6 on: May 29, 2021, 02:14:38 PM »

On 2m, there will be internal wiring fully long enough to send the trash out directly. 
Does the DW need to be doing any wash cycles to cause the issue?  or, just plugged in?
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K3UIM

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Re: Dishwasher RFI
« Reply #7 on: May 29, 2021, 02:47:54 PM »

Lois wanted me to tell you that she's totally happy with her dishwasher, as far as "noise" goes except for all the blasted mumbling that comes out of his mouth while working at it.
Charlie
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Charlie. K3UIM
Where you are: I was!
Where I am: You will be!
So be nice to us old fogies!!
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