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Heavy Noise Across 15 Meter Band, Any Idea What It Could Be?

Discussion in 'Videos and Podcasts' started by VU2JO, Feb 12, 2024.

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  1. VU2JO

    VU2JO Ham Member QRZ Page

    About five days back, I noted this extensive noise across the 15 meter amateur radio band. It persisted for quite some time and then subsided. I was using my modified 40 m inverted V antenna on 21 MHz, presuming that it will resonate as third harmonic.
  2. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    It would be very helpful to include audio of the noise for at least 15 seconds.
    VU2JO likes this.
  3. VU2JO

    VU2JO Ham Member QRZ Page

    I had taken only the picture of the waterfall for the heavy noise. Shall try recording audio next time, if I come across similar QRM.

    73 Bob. de Jon, VU2JO
  4. PA3GCJ

    PA3GCJ Ham Member QRZ Page

    First impression, looks to me as a free running oscillator.
    Could for instance be caused by local solar panel equipement.
    However in such case one would exspect it to be a repeating phenomena throughout the spectrum over a wide bandwitdh ( e.g. every 200Khz increase )

    Frank, de PA3GCJ
    VU2JO and N0TZU like this.
  5. VU2JO

    VU2JO Ham Member QRZ Page

    Thanks for the input Frank. I shall observe this further keeping this information in mind, at least for academic interest. There is a solar panel at a nearby home, which I can't do anything about!

    73 de Jon, VU2JO
  6. PA3GCJ

    PA3GCJ Ham Member QRZ Page

    As you most likely know, solar panel systems often come with pcb's called optimizers to evenout disbalance between panels.
    These optimizers often run with free running (unstable ) oscilators --> recognizable due to this frequency instabilities.
    I'm no expert on solar systems but can imagine some ferrite beads on the cabling close tot these optimizers helps avoiding radiation cause by common mode currents on these lines.
    It is an relative inexpensive solution which needs no electical physical altering of the solar system. ( wide variety of cheap beads in several sizes can be found online these days )
    VU2JO likes this.
  7. VU2JO

    VU2JO Ham Member QRZ Page

    Thanks a lot Frank for the useful suggestion.

    73 de Jon, VU2JO

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