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Solving RF Interference: A 1-Year Study of Sources and Solutions

Discussion in 'Amateur Radio News' started by K8QS, Sep 18, 2023.

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  1. K8QS

    K8QS Premium Subscriber QRZ Page

    See how I tracked all significant sources of RF interference for a year. Simple equipment and careful interaction with neighbors solved HF noise issues from numerous sources. Comments welcome. Quin, K8QS


    Attached Files:

    AF5SB, KQ1V, M7XCB and 10 others like this.
  2. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page


    Even in my remote QTH, I have devices that cause problems all the time. As an ARRL Technical specialist in Volunteer Consulting Engineer lots of people are requesting help all the time.
    This is a good start to watch your video.
    73 from,
    The K0UO " Rhombic Antenna Farm" miles of wire in the Air & On the AIR daily
    Last edited: Sep 18, 2023
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  3. K8QS

    K8QS Premium Subscriber QRZ Page

    Thanks so much, Steve. Let's continue to make this simple and something of an adventure for hams to find and fix RF noise issues. Things are getting worse largely because of the LED and wall-wart messes, but we can make progress and even have fun along the way. Quin, Ham Radio Perspectives
    VK5OHR likes this.
  4. KA2PTE

    KA2PTE Ham Member QRZ Page

  5. W5YZR

    W5YZR Ham Member QRZ Page

    I had the same problem with a lighted book case that was a major RFI source with that LED bulb! Great work Sir! Thanks!
  6. VK5OHR

    VK5OHR Ham Member QRZ Page

    My solution...

  7. DO1FER

    DO1FER Ham Member QRZ Page

    The latest video, after the last 12 month of first video, is amazing. It shows that there can be today much interferences behind the smallest electrical device. And this, what was to see in the video, is not an exception.

    But first I want to say that the TECSUN receivers are a great choice. Personally I use a PL-365 and I was surprised that its got the same quality in receiving like an old AOR 7030. But after the PL-365 there is the next model with the name PL-368x. Its good in price, tiny, got AM sync and other options. So not only for an RFI hunt pretty nice to use.

    In the video were said, that people should tell what happend around themselfs concerning to RFI problems. And when I heard about the problems which were made by Amazon Alexa, I began to laugh. So here is the story and before this, I have to say that Alexa is a 2M Band killer.

    It was around Christmas, were I got some heavy disturbances on the 2M band. Normally to that time, often just some christmas lights or anything else could produce this. So I stood calm and waited after Christmas, but the disturbances didnt want to go away. In the next step I called here in Germany the RFI clearance department of the Bundesnetzagentur. I described my problems and the operator of the BNetzA said that somebody will come by to check. So far, so good.

    After a longer period the clearance team came by and they found nothing outside on the street. To that my own problems got calmer in this case. The clearance team found just an abnormal signal with a low strength in the basement. They said that they cant do a thing against and went away. After this, personaly I felt a bit bad with my description of a bad signal across the 2M Band, because nobody found anything.

    Different month passed by and the disturbances came back. This time I called the clearance team again. They came by repeated time with a bad feeling, because they found nothing in the last time. And the situation repeated together with the weak abnormal signal. It was only to measure in the house and not outside on the street. It was now on the team to check the weak abnormal signal. The signal came from my neighbours below. The clearance team made an appointment with my neighbours and they had to come by the third time.

    To that appointment they checked before my problem in my flat again and they saw now crazy disturbances on my FTM-400 screen which makes it visibel (thats why I like it much). Then the team went down to my neighbours. Here they found after a longer search an Amazon Alexa, bad connected with cheap or wrong wires and with a wrong power-connector or adapter. To that I found by myself the source of the small bad signal at 145,150 MHz. Here is the center point of Amazons Alexas disturbances, when its on standby. And when its in wrong use, the complete 2M Band is killed and not to use until Alexa is shutdown again. And this is strange, because it only concerns the 2M Band.

    Here is now to see, that the problems will repeat around the world. And that the european CE sign is not really that what it was in the past. This because when changes are made with the devices, after it got its CE verification, no tests will be done again. And this is the cause of unawaited disturbances. To that some manufactures do this against their own better knowings about that, because they can sign the harmlessness by themself.
  8. DO1FER

    DO1FER Ham Member QRZ Page

    Sorry for a fault which I want to correct immediatly. The center point for Alexa is wrong, sorry. Here I ment a poweradapter for a Motorola cordless phone, which is another source of disturbances. Makes it not better. The rest of my description is ok.
    Last edited: Sep 19, 2023
  9. K8QS

    K8QS Premium Subscriber QRZ Page

    Thanks for your great responses, Cornelius. I just discovered ANOTHER source of noise and will post a picture and info shortly to this discussion. Quin, K8QS
  10. K8QS

    K8QS Premium Subscriber QRZ Page

    Okay, everyone, I turned the rig on yesterday to record a new video about how to call CQ . Low and behold, a new noise appeared across all of the HF bands but primarily on the lower frequencies (80 and 40 meters were terrible). So I first did the usual shutting off of circuit breakers in my own house, one by one, and eventually located the problem: My Keurig coffee maker in the kitchen. I tried putting filters on the AC cord, to no avail. Moreover, the noise is constant even when the coffeemaker is turned off. There is a clock that runs continuously in the unit so you can set it to come on at a particular time. My guess is that the switching supply in this machine went "bad." Wild. Quin, K8QS, Ham Radio Perspectives

    Attached Files:

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  11. K8QS

    K8QS Premium Subscriber QRZ Page

  12. VK5OHR

    VK5OHR Ham Member QRZ Page

    Just like this...

  13. W4PG

    W4PG QRZ Lifetime Member #279 Platinum Subscriber Life Member QRZ Page

    ANOTHER source??? Me-thinks you need to move! :D

    I have 2 homes, one in the middle of a very populated area in Tampa Bay (Clearwater, FL) where I have had a handful of RFI issues over the years but got them resolved. You might get a kick out of one of the more difficult issues I had, which I detailed HERE!

    The second home I have in SD is in a very sparsely populated area. I have essentially zero noise here and it's wonderful!

    Thanks for the video . . . it was very interesting.

  14. KB5ITJ

    KB5ITJ Ham Member QRZ Page

    Things I have found at my location causing noise on HF, wall warts, ethernet hub, early model of flat screen TV, DVD player and last the neighbors cows mooing just over the fence from my shack. Found most if not all major noise sources in my shack although back last Spring with the help of the local Electric Coop we did find a cracked insulator on a trammision line about a mile from my house. The most useful noise locating device turned out to be a pocket transistor radio although the Coop had an excellent directional hand held locating device that could also detect heat from power arcing around insulators and loose grounds.
    N4GST likes this.
  15. DO1FER

    DO1FER Ham Member QRZ Page

    Quin, your coffee machine got no european CE verification. I found some models of Keurig coffee makers together with the manual. These machines are spreaded around the world with Amazon. To that with local dealers in countries, where its not illegal to resell such things.

    And of course, here in Europe we are able to import by ourselfs such goods. But its often not the best solution.

    When those machines will make big trouble here and its found by some officials, it will go onto a kind of a "red" list of the Bundesnetzagentur. Here to show, that these machines to import or to use, is not allowed anymore. Further the coffee maker has to go to the disposal site or to the reprocessing, to save the different metals and so on. No need for to waste valuable raw materials.

    In the end, people who import such things are squandering their money.

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