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

[Tom W8JI]

> On 7/20/2010 12:01 AM, Don Wilhelm wrote:
>> ...so if you wish to
>> protect your K3 correctly (along with all the other equipment in your
>> hamshack), install some good lightning protection - single ground point
>> entry point for ALL lines coming into the hamshack - NO exceptions -
>> ethernet, telco, antennas, rotator, control lines, and yes even the AC
>> mains entry to the hamshack should enter through a single panel

That is good advice. All you need is one path into the operating desk or 
close to the operating desk that is not common to the entrance panel to undo 
the whole mess. That bonding, including bonding back to the mains ground, is 
more important than anything else.

> 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.

Of course it would. You could use proper MOV's and bypasses on ALL of the 
power mains leads to the SPG at the panel or entrance point. (It really does 
not have to be a through-hole two-sided panel, it can be a flat sheet things 
mount on.)

>> employing MOV or other protection devices present at that panel for each
>> and every line - this is the single most important point of lightning
>> protection.

Bonding and wire and cable routing to avoid ground loops through equipment 
is by far most important.

> Yet other knowledgeable people say that using MOVs in this way is apt to
> *cause* damage.

I don't know why anyone would say that. What kind of damage could it cause? 
To me, that makes no sense at all. MOV's might not help or might not be 
*useful* on all lines, but adding them would certainly not hurt anything. 
There would be no harm in peppering the panel with MOV's. It's a case where 
adding something might not always help, but adding it would never hurt 
anything.

For example.... I do not have a single special lightning protection device 
like a polyphaser on any coaxial cable at any entrance but adding the proper 
device would not hurt. I rely on my DXE and RCS-8V antenna switches for 
differential mode coaxial line protection because they do a much better job.

73 Tom