[RFI] 8 KHz spurs across much of amateur spectrum

[Lee STRAHAN]

Pete,
    As I recall you may be a Hi-Z user. If you are hearing these spurs on a Hi-Z array you may want to check all the elements. If one gets shorted or partially shorted to ground we have had cases where an array will pick up spurs similar to this. On almost all of the later versions of the Hi-Z amps there is 4 to 5 VDC present on the element. A simple test for grounding is to measure this DC on the elements. They should all match within 0.2 VDC of each other.
   If the noise is not on a Hi-Z array then look for a VFD running a pump or any other synchronous motor. They use switching frequencies this low.
   Good luck,
Lee    K7TJR   OR

-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of N4ZR
Sent: Tuesday, March 13, 2018 4:42 AM
To: RFI List <rfi at contesting.com>
Subject: [RFI] 8 KHz spurs across much of amateur spectrum

This may be a fool's errand, but just in case - I have discovered relatively pure carriers every 8 KHz 2-28 MHz (not heard on 160), tapering in strength as the frequencies get higher.  I assume some sort of switching power supply, but from what I've read most run at higher frequencies than that.  Is this by chance a signature of a particular source?

-- 

73, Pete N4ZR
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