[RFI] USB qrm - what to do?

[Huff David J]

I use a USB optical isolator. Starting at $36 online.
https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG/ref=sr_1_1?ie=UTF8&qid=1489414739&sr=8-1&keywords=usb+optical+isolator
https://www.adafruit.com/product/2107
http://www.bb-elec.com/Products/USB-Connectivity/USB-Isolators/USB-Isolators.aspx
Adding one of those, plus ferrites helps.
Thanks,
David
w0im