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Unsure of Mode at 14.090

Discussion in 'Working Different Modes' started by N6UGJ, Aug 6, 2010.

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  1. N6UGJ

    N6UGJ Ham Member QRZ Page

    Can anyone tell me what mode I am hearing at 14.090. No mode I have explored in using DM780 seems to be able to decode them.

    I have tried various modes in an attempt to decode these constant sigs, but to no avail.. Someone take me out of my misery, the curiosty is killing me.
     
  2. KR2D

    KR2D Ham Member QRZ Page

    "Constant sigs" is the key to solving this one. It's RFI from your LAN. Watch the blinking lights on your router - you'll see and hear the correlation.
     
  3. N6UGJ

    N6UGJ Ham Member QRZ Page

    actually, that can not possibly be the case as I do not own or use a router.
     
  4. WA4TM

    WA4TM Ham Member QRZ Page

    Do you have any neighbors?????
     
  5. N6UGJ

    N6UGJ Ham Member QRZ Page

    Ok I will reask the question.

    are there ever any potential sigs that might be transmitted on 14.090. Beacons, faxes something. The audio sure sounds like it is a transmission.
     
  6. N6UGJ

    N6UGJ Ham Member QRZ Page

    to answer your question since you took the time to respond. The nearest neighbor homes are to my east about 50+ yds away- and then we have to assume they have or use routers. Can some device from that far cause this?
     
  7. K8MHZ

    K8MHZ Ham Member QRZ Page

    It could be any form of digital signal, or it could be some sort of interference.

    Can you post a recording?

    Have you done stuff like turning off the power to your house and listening with a battery powered receiver to see if the noise goes away, or using a small shortwave receiver to attempt to locate the source?
     
  8. KR2D

    KR2D Ham Member QRZ Page

    What do you use for your internet connection? Any section of 100Mbps or Gigabit Ethernet is enough to cause RFI at that frequency.

    It could be from a neighbor, I see Ethernet RFI picked up by one of my antennas that is 150 feet way from my house (not sure if it's from mine or a neighbor's).

    Tune up and down the band - do you see the same signal elsewhere above 10 MHz? I get strong Ethernet RFI at 14.090 and 14.152, plus many other frequencies up through 6 meters.
     
  9. KE5FRF

    KE5FRF Ham Member QRZ Page

    To be certain, ANY digital signal can cause RFI.

    Tom W8JI confirmed my thoughts on this subject a while back.

    Digital circuits use square waves in clock circuits, digital music synthesizers and TV/monitor CRTs use sawtooth waves. Switchmode power supplies use square wave hard switching in the switching transistor.

    All forms of modern electronics out there have waveforms that create RFI through the generation of harmonics.

    If you live in an area where your neighbors are not too far from your antenna, there could be a whole HOST of interference causing devices that are constantly powered up and operating and therefore radiating signals. Sometimes you'll pick these up as "birdies" as you scan the bands. They do sometimes have a similar sound to a data transmission. In the case of a digital source, that's because it is!
     
  10. NX6ED

    NX6ED Ham Member QRZ Page

    Back in the late 1970's as a Data Systems Technician in the US Navy I worked with a civilian "Tempest" team that could "listen" to the digital data streams coming from another US Naval ship well over a mile away. My role was to look at the digital streams and identify the structure of the data which indicated which equipment it was originating from. This was not RF from radios, but just leakage from very well shielded cables and equipment. We could actually capture and decode the bits from that distance.
     
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