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What type of QRM/noise is this?

Discussion in 'General Technical Questions and Answers' started by KN6CSB, Jan 24, 2020.

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  1. KN6CSB

    KN6CSB Ham Member QRZ Page

    I sometimes get this type of QRN (mistake in title, got Q codes mixed) very strong, video in link is example of such instance where sometimes even Noise blanker on highest settings barely masks it. It sometimes falls on several portions of band. I think it sometimes just "disappears" until I notice it again, but can't be sure. the way it moves makes me think the receiver is being overloaded with AM harmonic? not sure if anyone can help appreciate it.
    Last edited: Jan 24, 2020
  2. W7UUU

    W7UUU Super Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    It's not QRM at all.

    It's QRN.

    Sounds like "cheap Chinese switching power supplies"

    A single such supply you could hold in your hand can wipe out all bands. - ask me how I know :D:D

    Either way, that is NOT QRM

  3. KN6CSB

    KN6CSB Ham Member QRZ Page

    doh, got my Q codes mixed..

    definitely man made.
    W7UUU likes this.
  4. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Yep, by definition QRN since it is noise.

    There are times that I think there needs to be a new "Q" signal for such like QRCPS for noise from cheap, or Chinese, power supply!

    Glen, K9STH
    W1TRY likes this.
  5. VK4GAP

    VK4GAP Ham Member QRZ Page

  6. KK4NSF

    KK4NSF Ham Member QRZ Page

    you've got two possibilities here:
    1- it a power supply.... and I agree with Dave that is a very likely possibility. I've run into that myself
    2- it's something else :D
  7. KN6CSB

    KN6CSB Ham Member QRZ Page

    I don't know what to think anymore,

    It sounds exactly like when I unscrew a connector and the common is hitting back and forth causing that rasping bump sound..

    then at times I swear I hear what sounds like modulation bleed in from my guess AM stations.. overall RFI has gone up past few days for me... powerline noise on 80 and 40 meters buzzing. now this.. Ugh. living in urban area trying to play radio on HF sometimes can be a real drag.
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    You're ~25 miles SE of me but I'm also in L.A. and don't have such noises.

    Well...I do, sometimes, but try to find the source of each one and eliminate them one by one. That can be almost a full-time job.:p

    But most of the noise sources I've had over the years don't have much to do with being in the city -- they're generated in my own house or in a neighbor's house within a block or two, almost always. You could live on a 500 acre ranch and have similar noise issues if they're coming from your own appliances.:)

    The "city noise" experience I have, which can be a bit bothersome, is on VHF. I can actually see a higher noise level if I point beams towards downtown/Century City/L.A. and it goes back down if I point in any other direction -- that is found mostly "at night," when downtown must be running every kind of lighting system imaginable and the sun noise is minimized. But on HF, that doesn't happen.

    Take your time and try to trace down sources.
  9. KN6CSB

    KN6CSB Ham Member QRZ Page

    Here's some more noise... mostly posting these for others who hear similar and to learn to identify it and for my own reference to check back on the frequencies later time and dates see how it is. I don't think i've heard this type on 40 meters.. definitely on 80 meters somewhere before though. I think this one is power line noise? not sure.

  10. KZ4AK

    KZ4AK XML Subscriber QRZ Page

    Sounds like power line (arcing) noise I have had. Of course, like others have said, could be something else... :D

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