[RFI] Power Line Radiated Interference Limits

[Steve Dyer]

For a quick and easy reading, the WSJT-X waterfall is quite useful. Just 
drop the rig into AM mode and see the bright line at 120 Hz and 
harmonics every 60 Hz across the whole pass band (at least at my QTH). 
Be sure to set Start to 0 Hz. You can roll over the waterfall or the pan 
with the cursor and read out the frequency.
I've also used Spectrum Lab to capture audio artifacts.
Soundcard Oscilloscope is useful to identify when you have multiple 
sources by observing the pulse trains and measuring the times between 
pulses. https://www.zeitnitz.eu/scope_en
Cant have too many tools.
73,
Steve
W1SRD

On 6/6/2022 13:24, Hare, Ed, W1RFI wrote:
> Actually, much powerline noise is rather steady, so it will show up as a solid block on a waterfall.  That is diagnostic that the noise is not coming from a switcher, but will not differentiate conclusively between electrical noise and perhaps noise caused by something not powerline-related at all.  The waterfall will not really identify 60- or 120-Hz modulation, so demodulating in AM and looking at the resultant audio is an important step.
>
> Ed
>
>
> ________________________________
> From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of Jim Brown <jim at audiosystemsgroup.com>
> Sent: Monday, June 6, 2022 1:45 PM
> To: rfi at contesting.com <rfi at contesting.com>
> Subject: Re: [RFI] Power Line Radiated Interference Limits
>
> On 6/6/2022 4:28 AM, Hare, Ed, W1RFI wrote:
>> You can also make a .wav or .mp3 file and run it through a free program called 'Audacity" and analyze that spectrum, with the understanding that your receiver bandwidth is usually limited below 200 Hz or so, so that 120-Hz component may be reduced in amplitude.
> The best diagnostic tool, by far, to identify power line noise, as
> opposed to electronic noise, is a broadband WATERFALL of either a
> receiver's IF or RF. Powerline noise and lightning static is arcing, and
> will show up as horizontal lines on a slow waterfall.
>
> Electronic noise is the harmonics of square waves used in switch-mode
> power supplies and other power control electronics like variable-speed
> motor controllers, which show up as vertical humps of noise spaced at
> 10-50kHz, and microprocessor clocks, which sound like carriers and show
> up as narrow vertical lines.
>
> Power line and other impulse noise is present at all frequencies, but is
> best chased at the highest frequencies where it can be heard.
> Traditional techniques apply. Electronic noise must be chased on the
> frequencies where it is heard.
>
> More on this in this here.
> http://k9yc.com/KillingReceiveNoise.pdf and
> http://k9yc.com/KillingRXNoiseVisalia.pdf
>
> 73, Jim K9YC
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi