The paper by Rudy Severns, EXPERIMENTAL DETERMINATION OF GROUND SYSTEM
PERFORMANCE FOR HF VERTICALS PART 7 GROUND SYSTEMS WITH MISSING SECTORS is
illuminating.
WX7G
On Feb 10, 2012 2:03 PM, "Guy Olinger K2AV" <olinger@bellsouth.net> wrote:
> The 120 comes from the watershed 1937 Brown Lewis and Eppstein study now
> found in the IEEE journals. There were distinct characteristics to 120
> times 0.4 wl (actually 115) that improved results even vs. 60.
>
> That a deficient radial system on one side has any significant reduction in
> that direction alone VS THE OTHER DIRECTIONS is a fairly well debunked
> idea. That the missing radials reduce radiation in all directions, due to
> diminished efficiency, is not disputed.
>
> 73, Guy.
>
> On Fri, Feb 10, 2012 at 2:54 PM, Herb Schoenbohm <herbs@vitelcom.net>
> wrote:
>
> >
> >
> > On 2/10/2012 1:11 PM, Milt -- N5IA wrote:
> > > If that is the case, WHY do the pro broadcasters install all 120
> radials
> > at
> > > full length; even bare wire buried a couple of inches underground?
> >
> > Answer:
> >
> > Because the FCC requires it as part of your AM application. Some
> > stations that were required to protect a distant station on the same
> > channel but away from the area they wanted to cover, even applied for a
> > waivers with a deliberately poor ground system in the protected
> > direction ...but the FCC said no way Jose. Another consulting engineer
> > when modeling a slant wire shunt fed and running test FSM noticed some
> > cancellation in the opposite direction of the slant wire shunt fed
> > tower. This appeared a sensible solution to enhanced protection without
> > the addition of another tower and expensive pahser, not to mention the
> > cost of additional real estate. Again the boys at 1919 M Street said
> > no. (The Portals today)
> >
> > With the price of copper skyrocketing the amount of theft in some parts
> > of the country is unbelievable. AM stations are immediate targets as
> > thieves just pull up the systems with a winch or just hook it to the
> > bumper and drive off into seclusion and roll it up in the back of a
> > truck. Some station owners in PR have opted to plow in barbed wire as a
> > lower cost alternative to bare copper. So far none of the barbed wire
> > buried ground systems have not been touched.
> >
> >
> > Herb Schoenbohm, KV4FZ
> > _______________________________________________
> > UR RST IS ... ... ..9 QSB QSB - hw? BK
> >
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
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