[Elecraft] K3/100 -Second floor- no RF ground ??

[Alan Bloom]

On Wed, 2010-02-24 at 18:16 -0800, Jim Brown wrote:
> On Wed, 24 Feb 2010 14:18:50 -0800 (PST), callen1155 wrote:
> 
> >I'm planning on purchasing a K3/100 but am concerned about my second floor
> >shack and RF problems.
> 
> The most important thing to understand is that a connection to EARTH has NOTHING 
> to do with RFI, or RF feedback, or any of the problems you are describing. 

It's amazing how widely the concept of ground is misunderstood.  For
years the ARRL Handbook repeated the myth that you need a good earth
ground to prevent TVI.  I think we finally got that straightened out.

People say that your low-pass filter won't work without a ground because
the shunt capacitors need to be "grounded" but then they are at a loss
to explain how low-pass filters work in satellites.

I think the fundamental problem is that people don't understand (or
forget) that "voltage" means "potential difference", the difference in
electrical potential between two points.  It makes no sense to speak of
the voltage "at" a particular circuit point unless you define the
reference point -- the place the other lead of your voltmeter or
oscilloscope is connected to. 

There can be 1000V difference in potential between earth and the chassis
of your radio and the radio will continue to work perfectly normally as
long as it is completely isolated from earth.  What matters is the
potential difference between the circuit nodes inside the radio, not the
voltage with respect to earth.

Al N1AL