[RFI] weird noise "waves" 60 khz Apaert

[Dave Cole]

On Tue, 2016-09-20 at 21:15 -0400, Pete Smith N4ZR wrote:
> 
> Today, for the first time, I looked at the bands on the bandscope of
> my RTTY Skimmer Server.  To my surprise, the background noise level
> shows very pronounced maxima every 60 *Kilo*hertx, with a notch next
> to each maximum.  I'm trying to get a screenshot to post, but my
> Skimmer PC just died.  In the meantime, does this ring any bells with
> anyone.
> 
> These are not discrete peaks - more like parabolic shapes repeating 
> every 60 KHz, but with significant energy on the upslopes.

Hi,
Take a look at:
http://nk7z.net/sdr-for-rfi-survey-p1/
Look at the individual per band spectrograms, you will see a lot of
Switching Mode Power Supplies, (SMPS), showing up in there as parallel
lines, and some moving around in frequency groups...  

If those look anything like what you are seeing, then you are seeing
SMPS.  Remember you are looking at in some cases 4 MHz of width, and a
time frame of 24 hours.
-- 
73's, and thanks,
Dave (NK7Z)
For software/hardware reviews see:
http://www.nk7z.net
-- 
73's, and thanks,
Dave (NK7Z)
For software/hardware reviews see:
http://www.nk7z.net