My guess is the way that they can claim 10 dB is by comparing the low
angle omnidirectional radiation of the vertical element to the radiation
pattern at the dipole's nulls, perhaps even over skip distances that
would require a low angle of radiation. So one could see a 10 dB
difference, but it isn't really "gain"
73,
Bob WB2VUF
Stuart Rohre wrote:
>
> Any Windom class antenna is only going to have radiation off the feedline
> approximating a low vertical at best. If the feedline is only quarter wave
> that is. If the feedline before the isolator is very long, then the windom
> can be looked upon as a feedline radiator loaded by a half wave off center
> fed dipole element. The half wave would look like a termination on the
> extended feeder length, and inherently, according to the British Antenna
> authority Les Moxon, that case would incur a 6 dB loss to the power
> available for radiation. His book on antennas that states that is the one
> sold by ARRL and RSGB.
>
> No ground mounted quarter wave or half wave vertical has 10 dB gain at any
> low angle, thus the manufacturers claim is specious at best. Their web site
> notes the claim is base on anecdotal accounts, which are notoriously
> affected by propagation, S meter inaccuracies, and operator subjective
> interpretations.
>
> The patterns on their web site do not contain any numerical scales! Nor
> reference to accepted standard antenna range references.
>
> The OCF antennas, of which the Carolina Windom is one, will radiate on 60m
> no better nor worse than a comparable dipole. See W6SAI's last antenna book
> on "Off center Fed Antennas" and the excellent web site by W4RNL, L. B.
> Cebik with a section on the OCF. < www.cebik.com>
>
> A tuner will be required with it on 60m just as on other bands for optimum
> frequency agility. The pattern will likely be offset as Bill Orr, W6SAI and
> Cebik show in their papers on the OCF family of antennas. A doublet fed
> with open wire or ladder line will have lower losses and can be used with a
> tuner as well for agility in getting best output on each channel.
> 73, Stuart K5KVH
>
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