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Author Topic: Trash at bottom of 40  (Read 3857 times)
WX2S
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Posts: 735




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« on: July 13, 2013, 05:52:45 AM »

I'm seeing some sort of persistent trash at the bottom end of 40 meters. Looks like a bunch of slowly sweeping lines about 2 kHz wide in my panadapter. Is anyone else seeing this, or is it local?

73, -WX2S.
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73, - Steve WX2S.
I subscribe to the DX Code of Conduct. http://dx-code.org/
WX7G
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Posts: 6078




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« Reply #1 on: July 13, 2013, 06:43:59 AM »

If it occurs day and night it is locally generated noise. What is the frequency spacing between the noise components?

If greater than 20 kHz it is probably a switching power supply.
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AC5UP
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« Reply #2 on: July 13, 2013, 06:51:34 AM »

I do a fair amount of SWL listening and there are bands of noise throughout the HF spectrum. Beeps, sweeps, whistles and even frequency selective hash........... Not coherent signals, just pockets of QRN.

Tune around below 7 MHz and you should hear plenty of odd sounds.
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WX2S
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Posts: 735




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« Reply #3 on: July 13, 2013, 09:15:13 AM »

If it occurs day and night it is locally generated noise. What is the frequency spacing between the noise components?

If greater than 20 kHz it is probably a switching power supply.
Small, about 50 hZ.
- WX2S
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73, - Steve WX2S.
I subscribe to the DX Code of Conduct. http://dx-code.org/
KB4QAA
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« Reply #4 on: July 13, 2013, 11:38:34 AM »

If you see signals that have a regular spacing, and if they drift, then it's a strong likelihood that it is a local signal from some sort of switching power supply, computer, TV, etc.
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KE3WD
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« Reply #5 on: July 13, 2013, 12:11:20 PM »

Stake near the lake, yo might be able to stun fish and frogs, but it won't help yer signal get out and may make thing worse. 
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WX2S
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« Reply #6 on: September 14, 2013, 03:03:47 AM »

Found the cause: Fluorescent lights in the kitchen.

73, -WX2S
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73, - Steve WX2S.
I subscribe to the DX Code of Conduct. http://dx-code.org/
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