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

[Tom W8JI]

> I've been thinking about how one might go about adding some protection
> for the apparently fragile (and expensive) RS-232 port on the K3.  It
> might be possible, if the components were small enough, to add them on
> the KIO3 I/O daughterboard, or perhaps on a little external board
> mounted at the port.

The ideal solution is to use a shielded cable, the shortest possible cable, 
and have the frame or cabinet of the computer grounded to the same station 
common point as the radio and all other gear.

Nearly all of the solution is in how you wire the desk and the radio room 
antenna cable and power entrance.

73 Tom