On 11/10/2020 11:32 AM, Jeff (W4DD) wrote:
This does bring up an interesting question. How is the LED string really
powered.
No question that it's an SMPS. Yes, products are harmonics of the
switching frequency, but many factors affect how their their strength
varies from one part of the radio spectrum to another. By far, the best
way to evaluate their noise is to first identify their signal in a ham
RX, preferably one having with a waterfall display, then poke around the
unit and its wiring with a battery-operated RX tuned to those frequencies.
Unless you're listening to traffic on the aircraft band or trying to
work small signal DX on 2M, listening on those bands is a poor way to
approach any ELECTRONIC noise, just as it's a great way to chase the
IMPULSE noise generated by arcing from neon signs and defective parts on
power lines.
73, Jim K9YC
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