It’s always easy to point a finger at others when you encounter noise while scanning the bands. More than often it is yourself who has to take the blame. In my case the switching power supply from my shack laptop is producing a lot of noise and artifacts, especially below 7 MHz. For a long time I had the plan to operate the laptop from my linear power supply and recently I got serious about it. A DC-DC step-up converter was bought for a mere US$7 and the following video shows initial results are very encouraging. The unit runs very cool so I am going to box it up and see if it can handle long operating periods.
Next up: isolating the USB connection. Stay tuned.