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75 meter intruder noticed

Discussion in 'Ham Radio Discussions' started by W2BLC, Jul 11, 2018.

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  1. W2BLC

    W2BLC Ham Member QRZ Page

    I have noticed a signal centering about 4.010 mHz, about 50 kHz wide, that emits a buzzing noise on an apparent regular time frame (generally every two minute lasting about ten seconds). It does not appear to be heard outside of the 1 and 2 land areas. Personally, I have heard it in the mornings and evenings. Any thought as to what or who is transmitting it?
    Thanks, Bill W2BLC
  2. KK5JY

    KK5JY Ham Member QRZ Page

    50kHz wide? Do you have a spectrum picture (from a panadapter, etc.), by any chance?

    Have you talked to other people who also hear it?
  3. W2BLC

    W2BLC Ham Member QRZ Page

    Yes, that is how I know it is being heard mostly in the northeast. I was just on a net with members from north and south. Those in the north are hearing it - those in 3 and 4 land are not hearing it. It is not local to me - if that is what you were asking.
  4. KK5JY

    KK5JY Ham Member QRZ Page

    Yes, I was making sure it wasn't just a battery charger in the neighbor's house.

    50kHz is kind of broad for an HF communications system. I would expect an OTHR to transmit in short bursts, not one long chuck of time.
  5. W4KJG

    W4KJG Subscriber QRZ Page

    I presently don't have an antenna after moving to a new QTH. So, I can't confirm if it can be seen here.

    I say "seen" because I first found it when I got my first SDR. That was about 4-5 years ago. If it is the same signal I was seeing, it appeared to be a fast sweeping signal, made up of what looked like closely spaced/channelized very narrow swept pulse signals. It started just above 4.0 MHz. I don't remember how wide it was, but it certainly could have been 50 kHz wide.

    I'm in the Winchester VA area. My former QTH, where I would see the signal, was about 15 miles west of where I now live. I regularly saw this signal when the band was open for long skip. I also assumed it was not local because of QSB.

  6. N1SZ

    N1SZ QRZ Lifetime Member #233 Life Member Platinum Subscriber QRZ Page

    What is the frequency of the “buzz”? As KK5JY points out, spectral plots/screen shot or an audio clip (YouTube) would be helpful.
  7. W2BLC

    W2BLC Ham Member QRZ Page

    It is a low frequency, perhaps around 30 cps. I cannot provide plots etc. It was the topic of discussion on several nets this morning and evening. I am surprised at how little interest there is in it.
  8. KK5JY

    KK5JY Ham Member QRZ Page

    I wonder if this station has drifted off-frequency, or might be generating some new spurs?

    Being in eastern Europe might also help explain the limited reception in the US northeast.
    W7UUU likes this.
  9. W2BLC

    W2BLC Ham Member QRZ Page

    Not similar. It is solid for 10 seconds at a much lower audio frequency. Cycles every 2 minutes.
  10. W2BLC

    W2BLC Ham Member QRZ Page

    If your ox is not being gored - perhaps, you do not really care!

    That said, a couple of days ago the signal changed and is now running 50 seconds on and 70 seconds off. It is easily heard on the upper 25 kHz of 75 meters and well into the MARS frequencies. It is interesting looking at it on a scope - should you have a panoramic display.

    As the signal has changed considerably, I have to wonder if the waters are being tested. 10 seconds a minute duration brought no reaction - so the increased length of each transmission to 50 seconds duration. What will be next?

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