[RFI] Splatter from AM Radio Station WNTS Indianapolis and Resolution

[Hare, Ed, W1RFI]

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 at contesting.com> On Behalf Of David Eckhardt
Sent: Tuesday, October 26, 2021 6:07 PM
To: Gary Smith <wa6fgi at steeltrails.net>
Cc: Rfi List <rfi at 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 at 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 at contesting.com] On
> Behalf Of Cortland Richmond
> > Subject: Re: [RFI] Splatter from AM Radio Station WNTS Indianapolis 
> > and
> Resolution
> >
> >
> >
> > _______________________________________________
> > RFI mailing list
> > RFI at contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
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>


--
*Dave - WØLEV*
*Just Let Darwin Work*
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