[Elecraft] 80 Meter Verticals

Wes Stewart wes_n7ws at triconet.org
Tue Feb 28 12:37:13 EST 2017


Ted,

You need to read W7XC's (SK) article in QST Mar 1990, pp 26-30


On 2/27/2017 4:13 PM, Dauer, Edward 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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