Topband: Ground loss query (re inverted L, antenna radiation resistance, & Jerry Sevick)

[Guy Olinger K2AV]

This IS true for some hams, because their counterpoise situation is quite
lossy. It would definitely not be true over a commercial dense radial system
that was in good repair.  It's very easy to measure by starting with a dense
radial system and removing radials between subsequent measurements.  I've
done some of that myself.

It becomes critical for a ham if their circumstances will not allow an
efficient radial system.  Then the name of the game becomes doing anything
that will reduce ground losses, which would include somehow avoiding a high
current feed when the ground/counterpoise connection is unavoidably lossy.

The issue in the commercial controversy referred to, for me at least, would
be accurately quantifying the "quality" of a radial system to come up with a
sufficiently questionable field.  How do you do that?

73, Guy.

On Wed, Oct 19, 2011 at 7:50 PM, Herb Schoenbohm <herbs at vitelcom.net> wrote:

> On 10/19/2011 2:28 PM, shristov wrote:
> >
> >
> > Folding has nothing to do with either radiation resistance or ground
> losses.
> > It is impedance-transforming device only.
> >
> > You've just performed 1:4 impedance transformation, nothing else.
> >
> > 73,
> >
> > Sinisa  YT1NT, VE3EA
> Sinisa,  A well known broadcast consulting antenna group Mullany and
> Associates made a detailed NAB presentation in the 60's on why a folded
> unipole and a cage feed made significant improvements for stations with
> questionable ground systems. They presented  FSM reading with and
> without to prove their point.  From that point on it became sort of an
> urban legend.  Other studies have discounted the claim completely. The
> acid test by du Treil, Lundin, & Rankin out of Sarasota, FL, was
> ungrounding and directly feeding a tower and hooking the cage to the
> feed point and getting exactly the same FSM reading at 1 mile with when
> the cage was fed unipole style! Their findings were presented at the
> 1996 NAB Broadcast Engineering Conference.  The original Mulany papers
> in the early 60's suggested that by raising the feed point impedance
> less current was flowing in the ground system thus improving the overall
> efficiency.  Many hams still believe that is still true.  Thanks for
> the  clarification.  But the legend continues to have legs.
>
>
> Herb Schoenbohm, KV4FZ
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