On 1/25/2013 6:15 PM, Greg Troxel wrote:
Unplugging the charger silenced the noise. Given that it seems coupled
to AC wiring elsewhere, it seems pretty clear that this was conducted
emissions. What isn't clear yet is if it started on the DC side and was
conducted to AC, or if it was generated in the charger.
You have just learned what many of us have known for decades -- ANY
switching power supply is a likely source of severe RF noise trash
unless it has been carefully designed to prevent it, it costs a few
cents to do that, so they are all noise generators. Switching power
supplies are almost universally used as battery chargers for everything
from cell phones to power tools to mobility scooters, in wall wart power
supplies, virtually all consumer equipment, appliances, for low voltage
lighting, and so on. When we hear noise in our radios, it is more likely
to be a switching power supply than a bad insulator on a power pole.
73, Jim K9YC
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