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 <[email protected]> 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 > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
