[RFI] shielded Ethernet cable, or not

[Jim Brown]

Some VERY important concepts, Laws of Physics-related.

A connection to Mother Earth has NOTHING to do with killing noise. 
Quoting the late Neil Muncy, W3WJE, who exposed "The Pin One Problem," 
as well as serious manufacturing issues with standard audio "rack cable" 
that made them susceptible to RFI, "The Earth is not a sump into which 
noise is poured.

The shield is NOT a "Ground." For shielding to be effective, it must be 
continuous, and connected DIRECTLY to the shielding enclosure at each 
end AT THE POINT OF ENTRY. Failure to do so is "The Pin One Problem," 
and as Neil predicted to me in bar conversation around 2003, it is the 
primary mechanism coupling RF noise into and out of sources.

My neighbor, N6TV, an IBM retiree who is also a serious contester, 
swears by shielded CAT cable. I've never used it -- but for reasons 
related to lightning protection, I use WiFi in place of wired Ethernet. 
I can do that because I don't need the speed and more stable latency for 
my operation.

A discussion of the issues associated with lightning protection is part 
of this slide deck pdf addressing Grounding and Bonding for hams.
http://k9yc.com/GroundingAndAudio.pdf  Don't let the word "audio" in the 
title throw you -- it's 99% about Lightning Protection and EMC. It 
started out in 2014 for talks I did at Pacificon and Visalia, and was 
updated a few months ago for a talk to the Northern California Contest 
Club. Most of its content was made part of N0AX's ARRL books on the 
topic of Grounding and Bonding, to which I contributed extensively.

73, Jim K9YC


On 9/25/2024 8:29 AM, Greg Troxel wrote:
> I would like to hear
> 
>    - opinions about the value of shielded vs unshielded Ethernet
>      (assuming chokes held constant).
> 
>    - opinions if sihelded outdoor to non-grounded switch with unshielded
>      back to grounded switch makes sense
> 
>    - experience of anyone who has faced this choice especially their
>      rationale before and their hindsight opinion later
> 
>    - experience of anyone who has done an unshielded to shielded
>      conversion and their hindsight opinion.
>