Need Help Identifying What I'm seeing on the Waterfall

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  • Updated 1 year ago
Any of you folks have an idea of what I'm seeing here on the waterfall. Seems to be occurring between 6 and 8 mhz. 4 lines then 5 lines alternating uniformly across the spectrum.

Thanks, 73 w7phg

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Craig Gagner

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Posted 1 year ago

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Photo of David-N5PSM


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I have seen that when my pre-amp was too high.....
Photo of Joe N3HEE


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New noise ? Time of day? Duration ? Need some clues to help solve this :)
Photo of bahillen


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This panafall shows appx 24 kHz rep rate with 48 kHz for pulses. The separation between sub modulation is 8 kHz.

Does the frequency at 7 MHz drift over time, iF so it is a harmonic of a very low frequency. Tune flex to 48 kHz and see what is there. Don’t think you can see 25 kHz but 48 and 72 khz may tell you something.

To do some analysis/ test take flex to your car with battery and drive a few blocks away to map what happens.

The N Koreans have over horizon radar in HF spectrum as an example but probably not your issue.

As said before, don’t overdrive you preamp. It can mix with broadcast stations and be like a transverter.

If it is a wallwart or led light hook flex to battery and break your main breakers. The flex is a tremendous to track and analyze interference sources. My friend had a light in his kitchen fail and replaced bulb with another one. His garage door stopped working. Who could figure with using same bulb type replacement.

If it is 7 MHz transmission every ham in your community should see same thing.

The above are just some ideas to figure it out. Is your neighbor growing some weeds in their attic.
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It may be a Wall Wort power supply, your station Power supply, computers-computer monitors, cloths Washer, furnace's, TV's, LED Light bulbs, Solar chargers, inverters and the list goes on and on can cause noise like this, and this is just in your home. 
With a laptop or Maestro plugged directly into the radio Ethernet (unless it's a M version Radio) put the radio on a 12 Volt battery and start turning off your breakers and see if it is coming from any of your home devices.
If doing this doesn't help it could be one of your neighbors has a problem device or it is on a outside source like street lights, or Electronic signs etc. 

Check with a HAM in your area to see if they hear it if they don't then the above will help, usually if things like Over the horizon radar or other atmospheric interference  is the culprit even people hundreds or thousands of miles away will hear it that you can check with.

YMMV and hope this helps  you find your issue.

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Andrew Thall

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I get a similar display when my wife starts the washing machine.  It looks like local interference from some electrical device.
Andy, k2oo
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Stan - VA7NF

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Locally I see a similar pattern, in my case a centre spike with +/- spikes (3 total) separated by 16Khz.  Appears to be on the neighborhood cable system wiring and originating from streetside cable amplifiers.
The battery and shut down household power is the first step - Note that your home network may connect radio and client or is the DHCP so, if not a 'M' system, ensure that connection does not go down with home power.