[Elecraft] RFI in audio chain

[Don Wilhelm]

Jan,

That 30-50 ohms resistance may be a shack safety problem.  Your shack 
ground rod must be connected to the Utility ground rod by a heavy 
conductor (#6 minimum, but #4 preferred).

That ground is only for AC safety and some part of lightning protection.
It does not present an effective RF Ground.  To use an example, consider 
an 8 foot connection to that ground and think of a 10 meter signal.  
That 8 foot connection is about 1/4 wavelength, so while the impedance 
at the ground rod may be low, the impedance to 28 MHz RF at the shack 
end is quite high (due to the properties of antennas and transmission 
lines).  In other words, what you are viewing as an 'RF ground' at 10 
meters is instead exactly the opposite, it is a high impedance to RF at 
10 meters.

The proper place to solve RF problems is in the antenna field, and not 
by attempts (sometimes futile) to bond things to a driven ground stake.

73,
Don W3FPR

On 12/22/2015 8:40 PM, Jan Ditzian wrote:
>
>
> I also discovered that my RF ground point in the shack (back of the 
> Ten-Tec KW tuner), shows 30-50 ohms resistance vis-a-vis the 
> electrical ground terminals in the shack.  Another rod as part of my 
> RF ground system may be forthcoming.
>