I don't usually do digital modes on HF, but I've seen improper shield handling in USB cables. The shield of a shielded twisted pair cables (e.g. USB, Ethernet) must ground the shield at one side only (usually on the host side) but some cables/devices ground both sides, which partially defeat the purpose of shielding. I think it is generally a good idea to check whether the peripheral device leaves the shield pin of the USB connector unconnected, especially with noise-sensitive equipment like radio and audio.
A large clamp-on #31 ferrite core like Fair-Rite 2631181381 is handy for troubleshooting like this (though not lightweight for hiking operation). It's big enough that it can make a few turns of a USB cable as well as feedline coax on the core to see where the conduction path may be. #31 core inserts a greater choke impedance than #43 or #61 but like with any ferrite core it often requires multiple turns to see clear effects.
Another good tool to have is a USB isolator. There are a few chips that are used in many USB isolators, that electrically isolate the port for safety, and those are very lightweight.
Ryuji Suzuki AB1WX