[Elecraft] K3 RFI in transmitted audio [End of thread]

[David Herring]

Yes please do post back here the final outcome. While not strictly an Elecraft issue, it is one of interest.

Specifically, I'd like to know how one would properly bond equipment (I guess for DC and audio purposes) AND RF ground the same equipment at the same time. 

Thanks and 73,
Dave
AH6TD

Sent from my iPhone

On Sep 13, 2010, at 7:13 AM, "Eric Swartz - WA6HHQ, Elecraft" <eric at elecraft.com> wrote:

>  Jim, Don and Joe,
> 
> To keep list traffic reasonable, let's take this recurring discussion 
> off list to direct email for now. Once you have all agreed please feel 
> free post the results to the list.
> 
> Also, there is a lot of past info on this topic that is searchable in 
> the list archives.
> 
> Also, please keep all discussions civil on, or off, list.
> 
> 73,
> Eric  WA6HHQ
> Elecraft List Moderator
> -----
> 
> 
> 
> 
> 
> On 9/13/2010 9:08 AM, Jim Brown wrote:
>> On Mon, 13 Sep 2010 09:40:00 -0400, Don Wilhelm wrote:
>> 
>>> If we were discussing RF, then your single point ground connected to a
>>> low impedance ground for RF would be correct - keep the path to RF
>>> Ground the same distance for each piece of equipment. will achieve
>> what
>>> is needed for lightning protection.
>> I disagree with that concept as well. The notion that a separate wire
>> is required for each piece of gear to a point that is often at a fair
>> distance from a closely arranged collection of gear in a typical ham
>> shack when that gear is already well bonded together does not make
>> sense. How, for example, do we insure that each wire is the same
>> length, follows the same or a similar path, and thus has the same
>> inductance?
>> 
>> There is NO CONFLICT between bonding all equipment chassis together by
>> the shortest practical path, as I've outlined, and making one or more
>> bonds between that equipment and the earth electrode system (ground
>> rods).
>> 
>> Indeed, both IEEE Standards on Grounding and most building codes either
>> recommend or require multiple paths to ground for lightning protection.
>> A large part of the thinking behind that is that the inductance is
>> reduced by having multiple wires in parallel.
>> 
>> As hams, we tend to think of our antennas as the only source of
>> lightning ingress to our homes, but that is FAR from reality. It's like
>> looking at the circus elephant through a tiny hole in the tent. EVERY
>> CONDUCTOR that enters the house, and every conductor INSIDE the house,
>> is a receiver for energy from lightning. That's why IEEE Standards and
>> nearly all building codes call for ALL non-powered metal to be bonded
>> together, and to one or more earth connections, and for all earth
>> connections to be bonded togther.
>> 
>> One other thought on this. In thinking about how all this fuzzy
>> thinking about so-called single point grounding came about, one source
>> of it might be equipment with a pin 1 problem. If, for example, the
>> bonds to the equipment are improperly made to some point OTHER THAN THE
>> CHASSIS, then yes, lightning current WOULD go through equipment if it
>> was daisy-chained. But that's not a GROUNDING problem, it's an
>> EQUIPMENT problem, and it's IMPROPER bonding.
>> 
>> The good news is that I don't recall ever seeing ANTENNA connections in
>> ham gear with pin 1 problems (except, perhaps, for an occasional RX
>> antenna). It's only the audio and control wiring, and an occasional IF
>> output.
>> 
>> 73, Jim Brown K9YC
>> 
>> 
>> 
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html