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Anyone recognize this EMI?

AA5JD JohnAA5JD John Member ✭✭
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.image


  • Michael CosloMichael Coslo Member
    edited October 2016
    Look for a electronic dog fence nearby. 
  • George KF2TGeorge KF2T Member ✭✭✭
    edited February 2019
    Have a similar signal here that started when the Halloween decorations went up. Really annoying!
  • Bob - W7KWS -Bob - W7KWS - Member ✭✭
    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.

  • Ross - K9COXRoss - K9COX Member ✭✭
    edited September 2018
    The curse of the Flex. you can see all of the contamination across the spectrum. 
  • DH2IDDH2ID Member ✭✭
    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.
  • Ross - K9COXRoss - K9COX Member ✭✭
    edited October 2016
    How about a blessing
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    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.
  • Ross - K9COXRoss - K9COX Member ✭✭
    edited October 2016
    I guess I nailed it with both comments
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
  • N6OILN6OIL Member ✭✭
    edited December 2016
    You know another good thing about the panadapter  you can see the interference coming, like radar type sweeps.
  • Bob - W7KWS -Bob - W7KWS - Member ✭✭
    edited December 2016
    My 6300 is the best spectrum analyzer to 54MHz. that I've ever used in forty years of engineering.
  • Michael - N5TGLMichael - N5TGL Member ✭✭
    edited December 2016
    Looks similar to what I see when our washing machine is running. 
  • Ken - NM9PKen - NM9P Member ✭✭
    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
  • Chris Tate  - N6WMChris Tate - N6WM Member ✭✭
    edited April 2017
    Sure looks like the Kenmore Front loading Washing Machine curse to me.....
  • Ross - K9COXRoss - K9COX Member ✭✭
    edited June 2017
    Fortunately I do the laundry
  • AA5JD JohnAA5JD John Member ✭✭
    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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