+9 noise level 256 days a year. any help?

Discussion in 'General Technical Questions and Answers' started by N9ZDZ, Mar 30, 2019.

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  1. KP4SX

    KP4SX Premium Subscriber QRZ Page

    I note you said "256 days a year". Was that intentional? That corresponds to a business location that might be open during the week and closed on weekends. Is the noise 24 hours a day?
     
  2. N9ZDZ

    N9ZDZ Ham Member QRZ Page

    yes all the time never stops
     
  3. KP4SX

    KP4SX Premium Subscriber QRZ Page

    256 or 365 days a year?
     
  4. N9ZDZ

    N9ZDZ Ham Member QRZ Page

    yes sorry for the typo 365 days a year lol.
     
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    Anything on the desk with power can hose a reading on a HiZ meter.

    I bet you put out more voltage than your desk. Hook it to your finger for test.

    Why does your wife make you stay in the basement ? I have a dog house. :)

    Good Luck.
     
  6. PA1ZP

    PA1ZP Ham Member QRZ Page

    Hi

    I would say there is some switching power supply bothering you.
    Its noise is transfered to the mains of the house, but that hasn't got to be your mains or from your house.
    i always "sniff" around with a very small short wave portable AM radio , when I get close to the mains of my house the radio will be bothered with QRM.
    When I sniff around a lightbulb qrm.
    Your lucky you can still hear stations.
    I had S9 + 25 dB QRM on 80 mtrs for years.
    Even the ground of my house was poluted by electronic junk 2 doors from my house, and as my and their house were running the same phase of AC it planted itself through my house and the house of my direct neighbours.
    i needed to recieve with Websdr reciever and TX myself.

    Could be a light dimmer dimming halogen spots, could be bad LED lights, could even be a simple battery charger for battery powered tools.

    Could be a bad wall wart charging a phone, so much electronic junk nowadays poluting the AC net.

    73 Jos
     
  7. WQ4G

    WQ4G Ham Member QRZ Page

    Have you tried grounding your metal desk? Does the interference go away when you disconnect the antenna?

    The ARRL has some sound files, on their web page, that might help you determine WHAT is generating the RFI. It is a bit easier to track down the source(s) of RFI if you can determine what type of device generating it. I see from the map on your QRZ web page that you live in town. Do any of the nearby businesses have any Neon Signs? A malfunctioning Neon Sign can sometimes be heard in your receiver from several blocks away.

    I have experienced / do experience lots of RFI at my QTH. Most of it is power line RFI and I have been working with the power company to locate and fix some of it. So far they have found and fixed at least a half dozen sources. One source, located about a block from my QTH, was causing RFI up and down the lines for more than a mile in each direction and in all the associated lines. According to the crew that fixed the issue the RFI was being generated by a loose washer on an insulator.

    Dan KI4AX
     
  8. N9ZDZ

    N9ZDZ Ham Member QRZ Page

    yes when I disconnect the antenna the noise goes away .
     
    K2CAJ likes this.
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    It almost always does.

    But, some RFI (noise) can be common-mode conducted, carried by the outer surface of the outer conductor of your coax. In some cases, that can be reduced or even eliminated by a good ferrite line isolator.

    I use those, the "grounded" type which includes not only a lot of ferrite to choke the common mode current but also a ground strap to assure the coax outer conductor is grounded on the way into the house. Cheap thing to "try," just in case it works -- if it doesn't, just leave it in place anyway, as it certainly can't "hurt.":)

    Many vendors sell these all assembled and ready to install...MFJ has one for $29 that seems as good as any others; they can also be homebrewed for maybe half that cost and an hour of time.
     
  10. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Ok, I see you answered some of my questions, I just missed them above.

    Please post a video in which we can clearly hear the noise, using AM mode on the radio. That might be very helpful in distinguishing power line arcing noise from some electronic source.
     

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