Hello!
One of my most used setups at the moment is Spyverter + HF modded LimeSDR USB that I use with a laptop computer.
However, when my laptop is connected to a charger I experience severe noise issues in the lower part of the HF spectrum (as expected).
I have tried powering LimeSDR via a barrel jack from a battery pack, but it doesn’t change anything. I know that it is powered from the pack because I monitored the battery current being drawn and observed about 820-1100 milliamps being drawn from it.
I suspect that the noise gets its way into the device using either the power rails of the USB cable or the data pins themselves.
I have tried naively to cut the power pin in one of my tested working USB cables, but this way it seems that my host controller does not want to enumerate the device. I will investigate this a bit further with an oscilloscope in the future.
I have seen devices that galvanically isolate USB devices, however I fell very short on options that would provide USB 3.0 compatibility.
I will very much appreciate any suggestions and ideas. Thanks in advance.