Re: USB Issue K3S

Clay Autery

Yep....  even a shielded USB cable will act up....  Often because the shield is not continuous or not terminated properly (or at all).
Thus, you need suppression from the ferrites molded on the cable OR get wire longer than you need and figure out which torroid and # turns you need to quiet it all down.

Clay Autery, KY5G
(318) 518-1389
On 09/21/20 09:33, Lyn Norstad wrote:

Or more likely, an issue with RF entering the USB circuit thru the cable. 


I have experimented with many USB cables over the years, and the only one I have found to consistently be trouble free is the Tripp-Lite (1 foot or 6 foot) cable with built in ferrite beads at both ends.  (Available on Amazon for less than $10.).



Lyn, W0LEN




From: [] On Behalf Of Clay Autery
Sent: Monday, September 21, 2020 7:29 AM
Subject: Re: [Elecraft-K3] USB Issue K3S


Sounds like its a USB port getting close to wearing out...  USB A-B is a lot less robust than USB C ports...  IMHO

Clay Autery, KY5G
(318) 518-1389

On 09/21/20 07:23, Alan Baker wrote:

It's possible that it's not just cable length, it could just be movement of the cable and proximity to 'something' else.


I've had intermittent issues with USB disappearing and I know for sure that at least twice it happened just after I reached over the back of the K3S to check a different connector.

My 'cure' so far has been to unplug the USB connector on the back of the rig and re-plug it, whilst watching the Device Manager display on the PC it's connected to. I have an extension lead on the USB cable and unplugging it there and re-plugging has no effect. Re-booting the PC has no effect. Of course it could be that something is not quite 'seated' in the K3S, but as all other I/O works 100% reliably, I have my doubts. As I have a mess of cables behind the K3S, I suspect some form of mutual coupling, which gets disturbed when I reach over. I guess I should try some ferrites.


I'm taking chances by writing this, as it's not happened for some time, so I better watch out when I next switch on. :-D




Alan. G4GNX



------ Original Message ------

From: gt0hof@...

Sent: 20/09/2020 22:50:20

Subject: Re: [Elecraft-K3] USB Issue K3S


I too had a problem when I reconnected a USB cable to my K3s. I found or so it seems the length of the USB cable is a problem. When I connected a 1.25 meter cable, the PC would see the K3s but would only RX with no TX, when fitting a 1.5 meter cable, it could not find the K3s at all. But when I tried a 600mm cable, BINGO, all’s well, PC found my K3s TX & RX. So I assume the shorter the cable the better, I am not a techy whizz kid so you tell me why 900mm of cable makes such a big difference? But it seems it does. Maybe my friend Andrew G8BYB might pick up on this thread as he may know more than me.




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