[RFI] More on 160 M RFI - significance of hum bands

[dalej]

Do you hear the noise on 10 meters,(6 meters even better if you have a gain antenna) if so it may be power line.  If you don’t it may be somebody's switching supply, charger or who knows what, but not power line.  

If I suspect a power line noise then I try to get a heading with my beam on 10 m. or 6, then walk the line with my airband walkie-talkie.  Makes for a nice walk anyway.  Once you find the pole or poles then call the power company and help them when they come out.  That has how I’ve handled power line noise in the past.  

If it’s a neighbors TV, computer, charger etc then that is a whole new ball game.  Hope that is not.  Check your own house first.  

73 and GL

Dale, K9VUJ


On 29, Mar 2017, at 17:29, Pete Smith N4ZR <n4zr at comcast.net> wrote:

I'm having more trouble than I expected localizing my power-line interference. In particular, one component of the interference varies from almost negligible to whopping big, as visualized on HDSDR, and often appears in wide bands 22 KHz apart..  See the Dropbox link <https://www.dropbox.com/s/qaxt7qnyl51hnp3/hum%20bars.png?dl=0> for a visual.  You can see the hum every 120 Hz on the audio display - when I move the AM passband away from the hum bands, the 120-Hx multiplesessentially disappear.  The bands themself vary, without apparent pattern, from very strong - as seen in the illustration- to invisblle/inaudible. Just now, they stuttered a few times and then disappeared from the waterfall (and the audio) entirely, in the course of a few seconds.  With the AM passband in one of the hum bands, the base noise level is about S9; without them, it is S7, which still isn't great, but worst things first.

Really puzzling - any advice on what I'm seeing and how to track it down will be much appreciated.


-- 

73, Pete N4ZR
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