[Elecraft] KIO3 failure mode

[Bob McGraw]

Many faults occur via the station ground system.  This fault indicated a 
difference in potential between the station ground and the AC Mains 
ground.  In many cases, the station equipment is connected between 
station ground and the AC Mains ground.   The nearby lightning strike 
produces a difference in potential between two or more grounds to which 
the station is effectively connected in series with these grounds. Thus 
the current flow is through the station equipment, even if power is off 
and antennas are disconnected.

My example:  A cow is standing under a tree during a thunder storm.  
Lightning hits the tree and the energy is dispersed through the earth in 
all directions.  Cow is connected via its 4 feet to the earth at 4 
places.   The difference in potential between the 4 connected places 
electrocutes the cow.   Lightning did NOT strike the cow.

If your station ground IS NOT BONDED to the AC Mains ground, (a) this is 
in violation of the NEC, (b) one has a high likelihood for damage in the 
event of a nearby lightning strike.

Second, each piece of equipment MUST be bonded to a common point.    
There is a difference in bonding and grounding. Station lightning 
protection and grounding is always outside of the structure, never inside.

Jim, K9YC and Ward Silver, N0AX in the ARRL book /GROUNDING AND BONDING 
for the Radio Amateur/ contains a wealth of correct information.  Use 
this information to defuse "old ham lore" regarding grounding.

73

Bob, K4TAX


On 8/24/2022 11:49 AM, elecraft-request at mailman.qth.net wrote:
> Message: 8
> Date: Tue, 23 Aug 2022 21:31:42 +0000 (UTC)
> From:cemilton at aol.com
> To:"ab7echo at gmail.com"  <ab7echo at gmail.com>,
> 	"elecraft at mailman.qth.net"  <elecraft at mailman.qth.net>
> Subject: Re: [Elecraft] [K3] KIO3 failure mode
> Message-ID:<903648173.1119840.1661290302636 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
>
> Not owning a K3, but have the KX3..............and other rigs!? Perhaps disconnecting the antenna (before and during an electrical storm)? from the shack hardware makes little boards like the K103 enjoy a longer life.? Just suggesting.? No disrespect in this comment.
> 73ChuckW4MIL

-- 
Bob, K4TAX