Re: [RFI] USB Cable Shield Resistance was: Re: [N1MM+] open question about RFI & USB

[Pete Smith N4ZR <pete.n4zr@gmail.com>]

Oh Joy - another thing to check.  I'm using a plain Ethernet Cat 5 patch 
cable from my amp to my computer.  Judging by how floppy it is, I 
suspect no shielding at all - but a question - if there were a shield, 
which pin on the Ethernet connector would it be?
73, Pete N4ZR

On 1/16/2024 10:22 AM, Jeff (W4DD) wrote:
> Pete, just another data point based on my experience with shielded Ethernet 
> cables.  Excerpt from one of my PPT's follows.  I found the shield connections 
> to be intermittent.
>
>
>
> Do Not Use Shielded Ethernet Cables from the Common Internet Sites
> The shield is not soldered to the metal RJ-45 shell.  I measured 2-20 ohms on a 
> group of 5 jumper cables shell to shell.  Mouser Electronics has Amphenol 
> Ethernet cables ($7) with the drain wire soldered to the metal RJ-45 shell at 
> both ends.  Resistance was less than 1 ohm for each of 5 cables measured (view 
> the spec sheet at Mouser.com).
>
> Jeff, W4DD
>
> -----Original Message-----
> From: RFI<rfi-bounces+w4dd09=gmail.com@contesting.com>  On Behalf Of Pete Smith 
> N4ZR
> Sent: Tuesday, January 16, 2024 9:32 AM
> To:N1MMLoggerPlus@groups.io; RFI List<rfi@contesting.com>
> Subject: [RFI] USB Cable Shield Resistance was: Re: [N1MM+] open question about RFI 
> & USB
>
> Interestingly, I just tested the shielding on a USB A to USB C cable I have, 
> which looked like it should be fine, with a transparent jacket over woven 
> shielding and a big ferrite bead - about 1 meter long, and measured 2.7 ohms - 
> not good.  What should be consider to be the upper permissible shield 
> resistance?
>
> Moving this issue to the RFI reflector now...
>
> 73, Pete N4ZR
>
> On 1/16/2024 5:01 AM, Janez Majdic via groups.io wrote:
> > Maybe also good to read:
> > https://www.yoctopuce.com/EN/article/usb-cables-shielding-matters-as-w
> > ell
> >
> > Regards, Janez - S51J
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