[TowerTalk] Vert. 1/2 wave dipole vs Hori. 1/2 wave dipole?

[Chuck Lewis]

----- Original Message ----- 
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
> However, now that you brought it up, I have also compared
> a quarter wave 20M vertical with 32 radials against a
> half wave 20M vertical with no radials.  Can't tell the difference
> on the air. (Both ground mounted).


L.B.Cebik would agree with this. His modelling of a center-fed inverted-L 
(basically a 1/2 wave inverted-vee rotated 45 degreees to put one leg in the 
vertical plane) showed insignificant improvement by adding radials. 
Furthermore, in the context of this thread, it's an antenna that merits 
consideration as a fine compromise between low-angle and higher-angle 
radiation, and certainly easier to erect on lowbands (65' rather than 130' 
on 80M) versus a full half-wave vertical. Feeding at the center provides 
high current at the top, the azimuthal pattern is almost circular at its 
resonant frequency, and no radials are required. You get benefits of both 
vertical and horizntal polarization. Sure, it's a compromise, but as a 
single antenna, a no-brainer. Given the variety of "Pseudo Brewster" angles, 
you're likely to have more success with this than with a single antenna of 
either pure horizontal or pure vertical configuration. You must dress the 
feedline away from the vertical element, and, if you use coax, isolate the 
feedline with a current choke; but for those with high trees, it's a fine 
choice. My 80M version is fed with RG-8X, is VERY effective both for DX and 
domestic paths, and quite insensitive to deviations from perfect geometry. 
Feeding with ladder-line would make this a good multi-band antenna, too; but 
the azimuthal pattern on harmonic frequencies would be, as expected, 
somewhat complex. You can check it out at Cebik's website under "All-Band 
Center-Fed Inverted-L".

Cebik points out that it can be also be voltage-fed fom the bottom, against 
a simple RF ground (no radial field) with equal success. [I can't wait for 
the responses on that, but will defer to Cebik's discussion!]

73,
Chuck, N4NM