The ARRL has only been saying for 20 years that grounding is not a cure-all for
RFI problems...
-----Original Message-----
From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> On Behalf Of David
Eckhardt
Sent: Tuesday, October 26, 2021 6:07 PM
To: Gary Smith <wa6fgi@steeltrails.net>
Cc: Rfi List <rfi@contesting.com>
Subject: Re: [RFI] Splatter from AM Radio Station WNTS Indianapolis and
Resolution
A proper "ground" or earth connection is *not *necessary for proper and
clean operation of an amateur radio station on HF ! ! In the past ARRL
has spread this rumor so much that it's become conventional knowledge and lore
of a good station installation. ARRL has finally come to terms with that bit
of miss-information in their publication of the "Grounding and Bonding" book.
Order one and have a good enlightening read!!! Whenever there is a problem,
the usual and stock comment is "ground it". This is baseless in most cases
when it comes to RF fields. There are three types of "ground":
1) The safety ground required by building code. This is the green wire that
should connect to any exposed conducting portion of equipment that plugs into
standard 120 VAC sockets in our homes.
2) ESD, static, bleed "ground". This may not actually be a ground or earth
connection, but just something to dissipate static discharges.
3) Lightning protection "ground" or return. This can get mighty expensive and
the cost of a professional (Uncle - been there, done that) is well beyond the
financial means of the typical amateur.
There ain't no such thing as "RF ground", only an RF *return*. The ISS doesn't
require a long wire connecting to earth to bidirectionally communicate to earth
via RF. The Crab Nebula doesn't require a ground to fill deep space with
copious amounts of broadband RF energy (and visible and IR and X-rays and gamma
rays and gravitational waves). When the Sun develops a major solar flare, it
doesn't require a "ground" to fill our local space (and kill the ionosphere)
with copious amounts of electromagnetic energy. What RF fields *do* require is
a return. In the case of a vertical monopole over a good radial system, the
radial system becomes the return (in a non-radiative manner). With the center
fed 1/2-wavelength dipole each half of the dipole serves as the return of the
"other" half of the dipole. The dipole and other similar radiating
configurations do not require a "ground" to function properly.
Here in N. Colorado about a decade ago, we had a serious RFI problem with a
large active matrix LED sign in Fort Collins. On contacting the owner of the
store, the first thing they commented was, "Oh, that sign is not
grounded....we'll fix that". A week later they called us back to test the
effectiveness of their grounding exercise of the metallic structure of the
sign. *Of course, grounding the sign made absolutely no difference at all.*
This was one of the few cases where the FCC had to get involved to cure the
problem. It took a threat from FCC of major fines to motivate the owners to
get off their hind quarters. Ultimately the supplier of the sign was
held responsible for eliminating the RFI. And........once again, it
turned out to be a problem with outsourcing certain aspects of the design to
China.
"Grounding" is most times ineffective in practice AND in theory of RF fields.
Dave - WØLEV
On Tue, Oct 26, 2021 at 9:32 PM Gary Smith <wa6fgi@steeltrails.net> wrote:
> Hi Joe and the list
>
> To your friends who are taking a whipping via harmonics, ask them if
> their station is properly grounded.
>
> The very few who have asked me about unwanted signals, when I ask if
> their station is grounded, I get some strange looks and mumbles and
> usually "I gotta go home and check".
>
> Gary...wa6fgi, located in what's generally known as"Baja North
> Highlands", 95842 country.
>
> On 10/26/2021 10:54 AM, Joe wrote:
> > Have good radio friends in North Highlands, California, that get
> > blasted
> by harmonics (While on 75 meters) from a clear channel AM station, KFBK.
> The station has been notified, multiple times, but they just shine the
> complaints on. They could care less about the interference to
> communications they are creating. The FCC is not concerned either,
> they are too busy trying to control the internet than address real FCC
> issues. L
> >
> >
> >
> > Joe W7RKN
> >
> >
> >
> > -----Original Message-----
> > From: RFI [mailto:rfi-bounces+w7rkn.7=gmail.com@contesting.com] On
> Behalf Of Cortland Richmond
> > Subject: Re: [RFI] Splatter from AM Radio Station WNTS Indianapolis
> > and
> Resolution
> >
> >
> >
> > _______________________________________________
> > RFI mailing list
> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
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>
--
*Dave - WØLEV*
*Just Let Darwin Work*
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