Frank and all,
Thanks for the example and I understand why it's a huge safety issue. My
Astron has a ground lug on the back and that's connected to the station
ground. It's still grounded to the AC ground for the house. In any case
though, I think Jim K9YC is probably correct. I went back through my
station log when I started making changes to remedy my RFI. Lifting the
ground did help a lot but that was before I updated all the bonding to my
equipment out to the ground rod. That alone could have reduced RFI. I won't
know for sure because I'm not going to undo all the ferrite I've put on all
the cables to my equipment to test a single change! :)
Thanks to all that helped with my situation. Have G&B book on Kindle and
going through it. I've removed the grounding section from my RFI video too.
73! Mark KA6WKE
Latest Video: https://ka6wke.net/gmail
Website: https://www.ka6wke.net
On Tue, Feb 4, 2020 at 9:59 PM <donovanf@starpower.net> wrote:
> Hi Mark,
>
> You misunderstand how short circuits to ground trip a circuit breaker.
> Lets examine just a simple case.
>
> Lets suppose you cut the ground wire in the AC power cord connecting
> your DC power supply to your AC power outlet. If a short circuit
> develops from the hot side of the AC power line to the metal case of
> your power supply -- perhaps a short circuit in a power transformer or a
> short circuited capacitor -- the metal case of the power supply is now
> energized at 125 volts AC. Death could result.
>
> Now if the ground wire had not been cut, the ground wire provides
> a path back to the neutral wire in your circuit breaker box. The same
> short circuit condition I described in the paragraph above will trip
> the circuit breaker.
>
> 73
> Frank
> W3LPL
>
> ------------------------------
> *From: *"Mark Schoonover" <mark@ka6wke.net>
> *To: *donovanf@starpower.net
> *Cc: *"RFI" <rfi@contesting.com>, "Amps" <amps@contesting.com>
> *Sent: *Wednesday, February 5, 2020 5:43:59 AM
> *Subject: *Re: [RFI] [Amps] Amp causing RFI
>
> Actually reviewing the wiring diagram for a standard breaker box and the
> ground wire isn't attached to a circuit breaker at all.
>
> https://www.do-it-yourself-help.com/circuit-breaker-wiring-diagrams.html
>
>
>
> 73! Mark KA6WKE
>
> Website: https://www.ka6wke.net
>
> On Tue, Feb 4, 2020, 21:25 Mark Schoonover <mark@ka6wke.net> wrote:
>
>> 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@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@ka6wke.net]
>>> Sent: Tuesday, February 4, 2020 8:26 PM
>>> To: Tim Duffy
>>> Cc: jim@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@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@contesting.com] On Behalf Of Mark
>>> Schoonover
>>> Sent: Monday, February 3, 2020 11:04 PM
>>> To: jim@audiosystemsgroup.com
>>> Cc: Amps
>>> Subject: Re: [Amps] Amp causing RFI
>>>
>>> On Mon, Feb 3, 2020 at 7:57 PM Jim Brown <jim@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.
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>> _______________________________________________
>>> RFI mailing list
>>> RFI@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
>>>
>>>
>
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