I can't comment on the folded counterpoise because I am not familiar with it. The "broadcast model" which I take to mean 120 radials is used because in the case of a 90 degree tower on medium wave, the earth current intensity is far enough from the feed point to necessitate a higher number of radials so that as they diverge, they are not so far apart from each other that the earth losses are unacceptable. Few hams have 1/4 w. towers for 160 m., and instead employ shorter vertical radiators such as inverted Ls* and Ts, (1/8 w. for example) so the ground current intensity is high much closer to the feedpoint. This means that fewer radials can be used because they are shorter and at their ends, are still an acceptable separation from each other. Of course, ground conductivity plays a part also. This is good news for hams who want to save money on expensive wire. All of this is detailed in the Griffith book I referenced previously.
73 Rob K5UJ *Unlike the T, the horizontal portion of the inverted L radiates. W1BB recommended extending radials that run along underneath it if possible, and I think that was good advice. On Sat, Jan 8, 2022 at 9:27 AM CUTTER DAVID <[email protected]> wrote: > > Rob > > I recall a discussion on here some years ago which proposed that, whilst > being an amazing antenna for top band, if you could achieve it, the broadcast > model was not necessarily the best use of resources for amateur purposes, on > the basis that broadcasters are mainly interested in ground wave to cover a > defined relatively short range service area, whereas amateurs a more > interested in dx. > > I don't recall how that discussion ended, but for purposes of saving wire, at > least, the K2AV folded counterpoise (FCP) must be about as good as anyone > could attain. How it performs against that broadcast model would be of > interest. > > David G3UNA _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
