This is bad advice, based on wandering around in the dark. See http://k9yc.com/KillingReceiveNoise.pdf andtoggle quoted messageShow quoted text
http://k9yc.com/RFI-Ham.pdf which are based on extensive, peer-reviewed research.
73, Jim K9YC
On 1/22/2020 7:08 AM, Bob McGraw - K4TAX wrote:
I am using some #31 material doughnuts which are 1.25"D x 0.25" H with an ID of 0.625". That 5/8" ID is just large enough for a USB connector to pass through allowing me to make a couple of turns of the cable through the doughnut.