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Pulse noise on 40 M

Anyone seen this before and what it is? It appears exactly at 6.00AM EST every day for the last couple of weeks. It goes away at some point overnight.
Radio is 6300 Version 3.1.12.
Mike - KB4HIN


  • ka9ees
    ka9ees Member ✭✭✭

    Must be local to you. What I've no idea. I'm on 40 now and don't see anything like that.


    Ed KA9EES

  • 1JR RSM
    1JR RSM Member ✭✭
    You maybe right. Another HAM in the Orlando area did not see that signal.
  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭

    Looks like a piece of dirty electronic equipment in your area, either your own house or your neighbour’s. I see occasional episodes of exactly the same noise in the evening when my neighbour turns on one of their TVs :-(

  • Stan VA7NF
    Stan VA7NF Member ✭✭✭

    I have a exceptionally high noise related to TV, but in the neighborhood cable distribution system. When a threshold count of users turn on their sets the distribution amp starts to oscillate (~230Khz) with harmonics and mixing products from 160M to well over 20M with some signals found up to 2M. Come late evenings as the sets are turned off the problem goes away. Definition of high noise is 40db over S9 from 200Khz to 80M.

    Your's repeats at 140Khz increments. Suggest you look at the 100Khz to 500Khz range for the first occurrence and track even multiples and then see if there are mixing products (not on the harmonic multiples) - That will identify if the source is strong enough to mix with BC band stations.

    After the "standard test" of running on battery and the house power is turned off you may be able to use a small hand made wire loop antenna (with good shielded feed line - Double shielded RG6 - TV cable is an example) and see where it is sourced. Also the flex is excellent with a sniffer antenna (1 inch diameter wire loop of say 10 turns mounted on a female panel connector) connected to a long cable. I personally like using the Maestro to take with me to see the results.

  • 1JR RSM
    1JR RSM Member ✭✭
    edited September 2020
    Here are more picture captured this morning. Th intensity of the offending signal varies from day to day.
    It start as the image here and the morphed into the earlier one I posted.
    Mike - KB4HIN
  • Joe N3HEE
    Joe N3HEE Member ✭✭

    I’m assuming you have eliminated your own house by turning off breakers ? The fact that it starts exactly at 6 AM every morning indicates it’s probably on a timer. Try to find out what time it is going off. Perhaps a grow light ? Any new neighbors in the past few weeks ? This should be easy to sniff out by sweeping the neighborhood with a portable HF radio and small loop antenna. I’ve had good success with finding and correcting noise sources this way. I use this simple to build loop. https://sites.google.com/site/tunedloops

  • 1JR RSM
    1JR RSM Member ✭✭
    Thank you for your comments. Nothing internally have change in my home. I did unplug each wall wart power supply and it made no difference. All tv's in the house have been removed from power source and still no change. As I mentioned before that the noise only started a couple of weeks ago. At this point I tend to believe the noise is external. I will discretely try and find the source. But in the mean time I will put the radio on battery with a laptop, put the circuit breakers to off/on and so on.
    Be safe.
    Mike - KB4HIN
  • 1JR RSM
    1JR RSM Member ✭✭
    Did some looking around and it seems that the offending signal might be from "Grow Lights" and don't let me try to explain what that means.....
    Mike - KB4HIN

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