Theoretically the more top loading you have, the higher the radiation resistance and the better the efficiency. So I like the T better than the L. I used to have an open wire fed doublet which could be switched to T configuration. It was very helpful to switch between horizontal and vertical polarization on 80 meters. -- Vic 4X6GP
On February 28, 2017 1:13:17 AM GMT+02:00, "Dauer, Edward" <[email protected]> wrote: >A question that’s admittedly a bit OT – though if I need a pretext, the >rig to be used is a K3 . . . > >I have been reading through the usual texts about vertical antennas for >80 meters, to replace the half wave dipole I now have and the Vee I had >but didn’t like. But I have not yet found the answer to one question I >am thinking about: The advantages or disadvantages of an inverted L >compared to other variations of the top-loaded vertical. > >Assume a 40-foot ground-mounted vertical section made with wire running >up a fiberglass mast. There could be a remote tuner or balun at the >base if it’s needed. The top of the vertical section would be guyed >with four lines more or less parallel to the earth extending from the >top tip of the vertical section to four suitably located trees. That >physical configuration offers three kinds of options. > >One is an inverted L. One of the four guy lines would be a wire making >the L and long enough to have the overall antenna resonate, with >nonconductive line from there to the tree. The other three guy lines >would be nonconductive for their entire length. > >Another would be the classic top-loaded “T” vertical. Two opposing guy >lines would be equal-length wire out far enough to achieve resonance, >with the other two nonconductive for their entire length. > >A third would be something closer to a capacity hat. All four of the >guy lines would start at the tip as wires, of equal length and just >long enough to effect resonance, with nonconductive rope from there to >each of the four trees. This variation might also have a square loop >connecting the distal ends of the four top wires. > >If the goal is to have the highest efficiency and the lowest net >radiation angle, and if the height of the vertical section is fixed and >the radial system is the same for each choice, does it matter which of >those three or four options is chosen? And if it does, how come? > >Thanks in advance for any lessons offered . . . > >Ted, KN1CBR > >______________________________________________________________ >Elecraft mailing list >Home: http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm >Post: mailto:[email protected] > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html >Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
