[Amps] [RFI] Amp causing RFI

[Mark Schoonover]

Frank,

FINALLY someone actually explains why what I've done is wrong. It's an easy
remedy to put things back. I'll also update my video and remove this
advice.

73! Mark KA6WKE

Website: https://www.ka6wke.net

On Tue, Feb 4, 2020, 21:09 <donovanf at starpower.net> wrote:

> DANGER
> DANGER
> DANGER
>
> Mark's advice should not be copied by anyone who respects their lives
> and the lives of anyone living in or visiting their shack or home.
>
> The ground wire in AC wiring provides a low resistance path back
> to the circuit breaker through a low resistance wire normally carrying
> very low current.  Cutting the third wire significantly degrades the
> performance and reliability of the circuit breaker protecting electrical
> equipment on that branch circuit.
>
> I have never encountered an RFI related problem that traces back
> to the ground wire in an AC power cord.   In the very unlikely event
> that you actually need to break this path, the only safe approach is
> an AC isolation transformer.  This approach is sometimes needed in
> very large industrial facilities where low level signals are interconnect
> equipment racks separated by hundreds of feet.
>
> 73
> Frank
> W3LPL
>
>
> From: Mark Schoonover [mailto:mark at ka6wke.net]
> Sent: Tuesday, February 4, 2020 8:26 PM
> To: Tim Duffy
> Cc: jim at audiosystemsgroup.com; Amps
> Subject: Re: [Amps] Amp causing RFI
>
>
>
> There can be two paths to ground. One from the back of your equipment to
> the station ground then back to house ground. The other path is from the
> ground in the outlet back to breaker box to house ground  then back to
> station ground. That creates a large loop depending on how much AC wiring
> involved.
>
>
>
>  I use several of those three prong to two prong AC adapters to break the
> path in the AC ground leaving just one path to ground through station
> ground. All chassis grounds are connected to AC ground so electrical safety
> isn't compromised. Really cleaned up a lot of noise with my station.
>
>
>
> The main video about RFI on my website I drew it out on a whiteboard. It's
> about 2/3 of the video.
>
> 73! Mark KA6WKE
>
> Website: https://www.ka6wke.net
>
>
>
> On Tue, Feb 4, 2020, 16:32 Tim Duffy <k3lr at k3lr.com> wrote:
>
> Hello Mark,
>
> I am confused. What does a connection to earth ground have to do with
> ground
> loops?
>
> 73
> Tim K3LR
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Mark
> Schoonover
> Sent: Monday, February 3, 2020 11:04 PM
> To: jim at audiosystemsgroup.com
> Cc: Amps
> Subject: Re: [Amps] Amp causing RFI
>
> On Mon, Feb 3, 2020 at 7:57 PM Jim Brown <jim at audiosystemsgroup.com>
> wrote:
>
> > On 2/3/2020 7:48 PM, Alek Petkovic wrote:
> > > ndeed. It has also helped me and most ham friends I know on numerous
> > > occasions.
> > >
> > > Adding a few shallow buried wires to the ground rod has also worked
> well
> > > for me.
> >
> > Balderdash. The earth is not a sump into which noise, RFI, and other
> > trash is poured. Comments like this bring to mind the infinite number of
> > monkeys and typewriters producing Shakespeare.
> >
> > 73, Jim K9YC
> >
> >
> What having a decent ground does is eliminate the possibility  of ground
> loops provided the ground is lifted from the third pin of the AC plug. I
> did a comprehensive RFI video on the subject and show how ground loops can
> happen and what to do to eliminate them. Quite possibly the #1 cause of
> RFI. You can watch the video in the link below.
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