[RFI] USB port closing

[Mike Smith VE9AA]

Martin, 

Also try to insure it’s a quality USB cable.  Some have little or even no
shielding. Fatter may (or maynot) be better. I think you can Ohm out shield
to shield, end to end to see if they’re electrically connected. If yes,
proceed.

In my case (laptop, 2 radios in SO2R etc.) I had RFI on certain bands with
as little as 5 watts !

Ultimately, replacing cables, adding ferrites –AND GROUNDING MY USB BUS, was
what solved my issue.

I took a tiny #26 wire jumper and wrapped it around the outside shield/shell
(fat metal part, not the control or 5v terminals) of one of the USB cables
where it entered my laptop\s USB port. This particular cable was for rig
control of one of my Icom IC-7410’s.  I then attached that jumper to a
slightly fatter wire and ran that to my station ground a couple feet away. 
99% of my constant RFI problems were solved with that one little wire.  
I take no responsibility if your buddy blows up his laptop by doing this. 
This is just what worked for me.
I do have some experience and qualifications in electrical and electronics
but am not an EE

Verify and consult others before trying.

GL

Mike VE9AA

Mike, Coreen & Corey
Keswick Ridge, NB

Hi,

I'm writing this for a friend. He has an Icom IC-7610 connected to a laptop
running Win4Icom. At anything over about40 watts it doesn't take many FT8
transmit cycles before Win4Icom will report a connection error,the error log
shows port closed and the author's statement in the alert box that appears
is that this is most likely caused by RFI. Accordingly, we want to deploy
suitable ferrite on the USB cables. My thinking is that 3 to 4 turns around
one of the medium or large type 31 snap on's that DX engineering sells, at
each end of the USB cable, would be a good start.

Is my thinking here sound or are there other things we should try first?

Thanks
Martin HS0ZED