Anyone recognize this EMI?

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  • Updated 2 years ago
I am getting this EMI on several bands 40-17M with what seems the strongest at 20m. I have put my Flex 6700 on battery with PC on the UPS and shut down power to the whole house. It's still there! I'm hoping someone might recognize this signal. I think it's a noisy UPS in the neighborhood but haven't tried tracking it down.
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AA5JD John

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Posted 2 years ago

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Michael Coslo

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Look for a electronic dog fence nearby. 
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George Molnar, KF2T, Elmer

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Have a similar signal here that started when the Halloween decorations went up. Really annoying!
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Bob - W7KWS -

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The screen shot below was from my new, Trane variable speed heat pump.  My picture looks different than your picture, probably due to scan rates and fundamental interfering frequency, but there are some similar characteristics, in particular the repeats across the band.  To me this indicates harmonics of a fundamental signal at a frequency equal to the distance between each repeat.

In my case it was around 5kHz. and came from the high power inverter that drives the compressor motor. Trane was very good applying effort to this problem adding filters to the 240 Volt input but in the end they didn't know much about RFI and were of no help.  They ultimately offered to exchange the unit with a lesser, single speed unit without an inverter.

As a last ditch effort I had the dealer follow the principals in the article on the subject in the August 2016 QST.  We installed as many snap on ferrites as would fit on every wire in the unit.  It worked and I'm back to normal for the second time in two years.  The first time it was grow lights down the street.

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Ross - K9COX

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The curse of the Flex. you can see all of the contamination across the spectrum. 
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Tim - W4TME, Customer Experience Manager

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We have a saying in support.  "The best thing about a Flex Radio is the panadapter and the worst thing about a Flex Radio is the panadapter".

Meaning you can now see all the RF "grunge" that was only noticeable audibly as clicks, chirps, tones and changes in the noise level.
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Ross - K9COX

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I guess I nailed it with both comments
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Tim - W4TME, Customer Experience Manager

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Bingo.
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Rory - N6OIL

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You know another good thing about the panadapter  you can see the interference coming, like radar type sweeps.
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Bob - W7KWS -

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My 6300 is the best spectrum analyzer to 54MHz. that I've ever used in forty years of engineering.
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Michael - N5TGL

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Looks similar to what I see when our washing machine is running. 
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Ken - NM9P, Elmer

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What timing pattern do you see with it?
Is it constant, or constant for several minutes?
Or is it a regular pattern every 10-30 seconds?

I have a pattern similar from a neighbor's Wash machine (I think) that sends strong spikes, followed by about 25 seconds of wideband noise, then a few seconds of silence, then repeats with a group of strong spikes, then the wideband noise, and over again....  from 80 all the way to 6 meters...and getting worse....

Longer patterns of several minutes might be a variable speed blower on an HVAC unit or a pool heater....

Ken - NM9P
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Chris Tate - N6WM, Elmer

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Sure looks like the Kenmore Front loading Washing Machine curse to me.....
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Ross - K9COX

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Fortunately I do the laundry
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AA5JD John

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George KF2T suggested Halloween decorations which may just be the answer. There are quite a few decorations in the neighborhood and I have been seeing the grunge for about 2 weeks. I haven't had time to try and locate the source but if so then they ought to stop next week or so. It can't be a washing machine or treadmill since I see it all hours of the day and night. Thanks for all the suggestions!