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
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