[RFI] Led swing clamp on desk lamps

[Jim Brown]

On 7/10/2022 6:18 AM, leonard keepers wrote:
> Hello group just curious. i have not yet purchased one of these lamps 
> but i see that they can be powered by usb.? how much of a powered usb 
> port or hub is needed for such a lamp to work properly. i am guessing if 
> it is plugged into ones computer it would add more work on the computers 
> power supply. thank you

Some accessories that power from a USB port include a DC-DC converter 
that, because it uses square waves for the process, generate massive RF 
noise. My neighbor, W6GJB, traced noise in his shack to USB-powered 
speakers.

73, Jim K9YC