What am I seeing?

Discussion in 'General Technical Questions and Answers' started by KZ8MAX, Oct 13, 2019.

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  1. KZ8MAX

    KZ8MAX Ham Member QRZ Page

    I've noticed when I go to certain bands at certain times, I get the following display of evenly spaced bars on my display. Does anyone know what this is? When I go to them it's just a high pitched sound.



    Attached Files:

  2. AA7EJ

    AA7EJ Ham Member QRZ Page

    woodpecker is back !
    K0UO likes this.
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    Cheap import switching power supply/wall-wart (likely in your own house) where the Asian builder is cheating by leaving out the filtering components so as to make an additional $1 per unit!
    N0TZU, YO3GFH, WA8FOZ and 2 others like this.
  4. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page


    Often, more like saving 5-cents! However, over thousands of units, those cents add up.

    Glen, K9STH
    N0TZU likes this.
  5. KZ8MAX

    KZ8MAX Ham Member QRZ Page

    Any suggestion on how to fix the crime perpetrated by this beast? I feel violated.


  6. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    RFI hunting is a weekly if not daily topic on The Zed. The ARRL has an excellent resource page.


    Quickie tip: Source is most probably a wall wart or electronic device in your home. Remember, no device is "Off" until it is disconnected from the electrical power source.
    K0UO likes this.
  7. WA7ARK

    WA7ARK Ham Member QRZ Page

    Unplug the last (newest) gadget you brought into the house... If that is not it, unplug the second newest one...

    If that doesn't do it, then here is what to do next...
    Last edited: Oct 13, 2019
    K0UO likes this.
  8. KZ8MAX

    KZ8MAX Ham Member QRZ Page

    Thanks for the help.. I thought wall wart was another name for Walmart... lol
  9. K6BRN

    K6BRN XML Subscriber QRZ Page

    Hard to get away from the noise "bars".

    Newer inverter based A/C and heat pump units also produce this signature as can inverter based washers and a host of other switching devices, including solar panel-embedded micro-inverters.

    At my CA QTH, I installed dedicated power from the home electrical entrance panel to my radio room, installed a dedicated grounding system in parallel with it and use common mode chokes on all of my antennas, plus a coax shield ground block for all lines to connect to before they enter the radio room. Then I made sure all antennas were as far away as possible from the main offenders.

    This helped quite a bit, but the interference is still there - just at a much lower level. It also varies quite a bit from antenna to antenna - I have wire, Yagi and verticals whose band coverage overlaps, so sometimes select antennas based on interference levels.

    At the radio end, I have an FTDX-3000, R75 and FT-991, all with decent DSP noise reduction. Plus I use an outboard CLRdsp noise reduction unit in series with radio audio. This combination is very effecive and is quite popular around here.

    Homes in Manhattan Beach CA are spaced about 8-10 feet from each other - so this is a very dense environment for electrical noise. But it's livable.

    Brian - K6BRN
    K0UO likes this.
  10. WA8FOZ

    WA8FOZ Premium Subscriber QRZ Page

    Find the offending device and replace it. As big and loud as the bars appear to be, it is probably in your own house. I get little skinny bars like yours from time to time on my display, but so far they have not been strong enough to have any practical effect. Probably from crappy switching power supplies elsewhere in the neighborhood.

    Good luck.

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