[Premium-Rx] Grounding Receivers

[Brooke Clarke]

Hi Blair:

Sorry for the late answer, but when this topic came up I called P.G. & 
E. who supplies my electricity and they just called back.
The short answer is that you can do what you want after the transformer.

It's my understanding that the power feed to your house is from a center 
tapped winding on the pole pig to prevent 12 kV from coming into your 
house if these was a primary to secondary short in the pole pig.  (this 
is part of the A.C. power system not invented by Tesla)  By grounding 
the center tap both at the pole and the house entrance panel the 12 kV 
goes to ground blowing the fuse on the pole pig primary.  This is the 
key to why the electrical code wants to see a ground at the entrance 
panel, sort of a belt AND suspenders approach.  I like the idea since 
this way a single point failure in a ground will not fry your house if 
there's a problem.

I actually had a failure in a wire between the transformer and my house 
when a gopher eat the insulation and the wire (no harm came to him).  
This causes an imbalance in the voltages on the two phases that depends 
on how well the currents are balanced.

The other two factors, noise and lightening have already been covered in 
prior responses.

73,

Brooke Clarke, N6GCE

-- 
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Blair Batty wrote:

>
>> Next, an isolation transformer to power the receiver is a big help,
>> especially if
>> it has low interwinding capacitance and / or Faraday shielding. Much 
>> of the
>> RFI on
>> longwave is capacitively coupled into the receiver thru the AC line,
>> especially the
>> 15.734 KHz horizontal oscillators in TV sets, and the COPIOUS 
>> harmonics of
>> same!
>>
>> Finally...  if possible, make sure that your receiver ground is TOTALLY
>> isolated from the AC power company ground.
>
>
> Hi Ben:
>
> Grounding is something I've been puzzling with.
>
> The AC power for my shack goes to a 240v, 15 amp Sola Isolation
> transformer, which isolates and voltage regulates my shack power.
> The Sola metal cabinet is bonded to the Utility ground wire. The heavy
> transformer inductance also kills any rfi and spikes.
>
> The ground wire of the Sola secondary output cable is connected
> to the shack's RF, antenna and equipment common bonding
> point (connected to ground rods), before going to AC outlets. So all
> equipment, antennas, and AC ground was isolated from the Utility
> supplied ground; and Utility power noise on the AC lines didn't get into
> the shack power.
>
> Unfortunately that arrangement is illegal. So I've connected the utility
> ground to the shack AC power ground by jumpering at the Sola
> Transformer. So my question is, do I leave the jumper in or not?
> I don't mind being illegal, if it's quieter and safe.
>
> Sincerely
> Blair
>
> p.s. Please reply directly, if you feel it's off topic.
>
>
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