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

[Edward R Cole]

Tom,

IN addition to bonding my radio ground rod to the electrical ground 
(on the other side of the house), I will have my radio ground going 
to my cable entrance plate.  From there I have two tables and my 
racks arranged in an U configuration with radio table facing the 
racks six feet across the operating space.  How should I run 
grounds?  My intention was to run a separate ground wire to a ground 
buss on the radio table an another one to the racks both tied to the 
copper bolt holding the outside ground wire.

The only dc-isolated wiring in my shack is the soundcard audio lines 
from radios to computers.  Everything powered with ac is tied to the 
safety 3rd wire in the house wiring.  -HV thru a 100-ohm/25w resistor 
, -24vdc, and -12vdc are all strapped to ground.  All coax lines 
exiting the room are grounded at the entrance plate.

See any problems with this?
Thanks,

Ed - KL7UW

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Message: 5
Date: Mon, 19 Jul 2010 15:01:31 -0400
From: "Tom W8JI" <w8ji at w8ji.com>
Subject: Re: [Elecraft] K3: Added protection for RS-232 port (summary)
To: <n4zr at contesting.com>,      "Elecraft List" <elecraft at mailman.qth.net>
Message-ID: <47AFA1A1234B442F8091CDCD3233240C at tom0c1d32a93f0>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
         reply-type=original

 > Consensus seems to be that grounding, particularly making sure that all
 > chassis are bonded together with the station entry panel and the
  ...snip...
 > 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



73, Ed - KL7UW, WD2XSH/45
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