[Elecraft] K3: Added protection for RS-232 port

[Paul Christensen]

> All of my hamshack equipment is on a single outlet.  This has me
> wondering whether a good quality connection between the entry panel
> SPG and the neutral *at the outlet* (it is less than two feet from
> the entry panel) would approach or achieve the objective of helping
> everything to rise and fall together.

In the U.S., tying the service entry common ground/neutral bond back to the 
shack outlet neutral is a code violation.  However, I see nothing in the NEC 
that prohibits an alternate grounding conductor to be added to the ground 
screw on a receptacle.  Still, I wouldn't do this unless you have reason to 
believe there's a high resistance between the receptacle ground point and 
the serving panel.

If you're going through the trouble of adding a ground conductor, I would 
studying code-compliant station grounding methods as shown on the K9YC and 
W8JI websites.

After establishing an effective station ground and if there's still a 
concern relating to the rise and fall potential created by surges on the 
grounding conductor in the shack, consider adding a whole-house surge 
suppressor only at the main entrance panel and not a sub-panel.  Also, the 
best method of adding secondary surge suppression on a branch circuit is not 
through the use of so-called "three modes of protection" MOV devices. 
Instead, consider using only single-mode to neutral protection.  The better 
units store the surge energy through a high C component and bleed the surge 
to neutral, rather than ground.  They're expensive units.  SurgeX and 
Brickwall are two manufacturers using this technology.

Paul, W9AC