N6RK wrote: The higher radiation resistance and lower ground loss of the
inverted L is illusory, because the additional radiation represents
horizontallly polarized waves, which tend to be inefficient for
communications purposes
on 160 meters most of the time, especially at typical inverted L heights.
K4SAV: It doesn't matter if the radiation is horizontal or vertically
polarized. It only matters as to the total strength of the pattern at
the desired angle.
N6RK wrote: If you do an NEC model with a second reference vertical, say
5 wavelengths away, and look at the amount of vertical power received by
the second reference vertical, then you will see that the horizontal
section of the inverted L contributes nothing, whereas a T top actually
increases received signal.
K4SAV: That is true, and if you sense the signal with a horizontal
antenna, the opposite will be true. Since the polarity of a sky wave
propagated signal is not predictable, the polarity of the generated wave
does not matter, only its strength at the desired angle matters (seems I
already said that). If you are interested in ground wave, that is a
different story. If you look at the far field pattern of these two
antennas you will see that the L produces a greater signal strength in
the direction opposite the direction the top wire runs away from the
vertical wire, even at very elevation low angles. In the direction
opposite that, the T produces greater signal strength. For high angles
the L produces a much stronger signal because the T has a null overhead.
Jerry, K4SAV
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