Ken can read emails but not post.
He brings up some good points which I concur with.
I will copy his text below.
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
====================================================
Hi Rick,
Again I cannot participate in the reflector because I am using webmail and
the reflector does not recognize me as a registered participant.
Regarding your comment about verticals working without radials. You are
correct, but there are some important details that should be pointed out:
1) Depends what you mean by "works." We all know people can make QSOs using
a light bulb or a poorly shielded dummy load, and have a really good SWR. It
works, but the efficiency is poor.
2) Yes there are vertical designs, such as center fed vertical dipoles which
are much less lossy than an end fed monopole without radials.
3) Any antenna that is close to the ground induces currents in the ground.
If the ground is resistive, these currents heat the ground, instead of
contributing to a stronger signal. Even an antenna which is fairly efficient
(such as a center fed vertical dipole) without radials can benefit from
radials, because the radials will reduce resistive losses in the ground. If
the antenna was tuned for a good SWR without the radials, and then the
radials are added, the impedance will change and without retuning one could
(incorrectly) conclude that the radials made the antenna worse. If properly
tuned the vertical with radials will be more efficient.
4) Antennas with very little resistive losses tend to have sharper
resonances. (Unless they are special wideband antennas such as discones,
conical dipoles, log periodics). The wider low SWR curve of a lossy antenna
is often misinterpreted to be "better" than a more efficient antenna with a
narrower low SWR curve.
A large proportion of the hams using verticals cannot get the vertical very
high off the ground, or their rooftop, so there will be significant ground
losses without radials, even if it can be tuned to give a low SWR.
Wish I could post that. You may if you care to.
Cheers, Ken N6KB
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