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" <olin...@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 <he...@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