Is there any truth in the theory of making the vertical radiator out of multiple wires such as ladder line and even adding a third wire woven through the ladder sections and fed on one wire? The physical result is three parallel wires but electrically connected so as to form and "up, down and up again" element. This supposedly raises the radiating element impedance relative to the fixed ground loss resistance. The idea I'm told, is that since the ground resistance (loss) is fixed at whatever it is but as the actual radiating element impedance is raised, the antenna becomes more efficient since the ground loss percentage of the overall feed point impedance is lowered. This impedance change happens in much the same way as a folded dipole feed is a higher impedance than a conventional dipole using a single wires. I saw this written up a few years ago as a means of increasing the overall efficiency of an inverted L for either 160 of 80 M.
I had an "L" made of the smaller ladder line on 160 with only four ¼λ radials on the ground that seemed to work fairly well. My plan was to install elevated radials, but that would have been a LOT of wire around the yard. Something broke on it after a year or so, and I never re-installed it. 73, Charlie k3ICH -----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Ron D'Eau Claire Sent: Tuesday, February 28, 2017 11:08 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] 80 Meter Verticals One characteristic of a "T", assuming the top wires run in opposite directions and are of equal length, is that radiation from the top wires is highly suppressed because they are fed "in phase" by the vertical section. That means that nearly all radiation is from the vertical section, whereas in an inverted "L" arrangement there is considerable radiation from the horizontal section. Some ultimate "T" type antennas for H.F. were the very short verticals documented by Jerry Severt (W2FMI, SK) using umbrella-like multiple top hat loading with many "spokes". The QST archives have his articles. 73 Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
