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

[Tom W8JI]

> Consensus seems to be that grounding, particularly making sure that all
> chassis are bonded together with the station entry panel and the
> powerline ground, is the best protection.  I think this likely is where
> I went wrong, because I had just completed the radio and had not yet
> grounded it to my station bus, which is 3/4" copper pipe behind the
> radios, wired to the station entry panel with heavy copper.  As I write
> this I'm in the midst of going through my station to make sure that
> everything is properly grounded.

Pete,

If you think of everything in terms of not having currents loop between 
different things on the desk, you would be much better off. If we think of 
it as grounding the strike, we can easily get into trouble.

With a second floor station I would have the entrance, if not really an 
entrance but an outside plate, at ground level outside and bonded to the 
mains ground. Then I would bring all the shack radio and computer power to 
that panel and MOV and ground it there, and bring everything (including any 
ground) in a bundle from that point upstairs. I would do a single point 
common at the desk and ONLY ground that point back to the lower entrance 
with a ground in, over, or along that bundle. The idea being to not create a 
loop.

My contest barn is that way, because the station is on the second floor. My 
house is similar.

The last thing you want is a big open loop, or a ground lead that routes in 
a way that encourages things to flow between power and control cables, and 
especially between different pieces of gear.

I've not had a failure with my K3 (or anything else inside the buildings) 
even though everything stays connected to all the cables, including antenna, 
control, and computer, and I've had dozens of lightning hits here just this 
year alone.

 73 Tom