Anyone recognize this EMI?

Answers

• Michael Coslo Member

  October 2016 edited October 2016

  Look for a electronic dog fence nearby. 

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• George KF2T Member ✭✭✭

  October 2016 edited February 2019

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

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• Bob - W7KWS - Member ✭✭

  October 2016 edited February 2018

  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 Member ✭✭

  October 2016 edited September 2018

  The curse of the Flex. you can see all of the contamination across the spectrum. 

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• DH2ID Member ✭✭

  October 2016 edited December 2016

  I won't call it a curse, because seeing so much of the spectrum helped me to get
  rid of a lot of rf pollutants in my flat and in the vicinity. I installed all of the
  switchmode chargers in my hobby room on a switchable power **** and
  with a lot of ferrite cores was able to get a much improved spectrum.

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• Ross - K9COX Member ✭✭

  October 2016 edited October 2016

  How about a blessing
  

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• Tim - W4TME Administrator, FlexRadio Employee admin

  October 2016 edited December 2016

  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 Member ✭✭

  October 2016 edited October 2016

  I guess I nailed it with both comments
  

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• Tim - W4TME Administrator, FlexRadio Employee admin

  October 2016 edited December 2016

  Bingo.

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• N6OIL Member ✭✭

  October 2016 edited December 2016

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

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• Bob - W7KWS - Member ✭✭

  October 2016 edited December 2016

  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 Member ✭✭

  October 2016 edited December 2016

  Looks similar to what I see when our washing machine is running. 

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• Ken - NM9P Member ✭✭

  October 2016 edited June 2020

  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 Member ✭✭

  October 2016 edited April 2017

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

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• Ross - K9COX Member ✭✭

  October 2016 edited June 2017

  Fortunately I do the laundry
  

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• AA5JD John Member ✭✭

  October 2016 edited December 2016

  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!
  

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