[Elecraft] 80 Meter Verticals

[Ron D'Eau Claire]

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

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Vic Rosenthal
Sent: Tuesday, February 28, 2017 4:01 AM
To: elecraft at mailman.qth.net; Dauer, Edward
Subject: Re: [Elecraft] 80 Meter Verticals

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" <edauer at law.du.edu> 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
>
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