Topband: [Topband] Inverted "L" vs." T"

[Guy Olinger, K2AV]

>>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.

5 wavelengths away is hardly in the far field, with some degree of common 
ground between. Even at a mile, one is still talking about ground wave, and 
to draw small distinctions, one needs a model that DOES groundwave, and 
DIRT, WELL.  Only the pro grade modeling programs do dirt even halfway 
decently.  As some others here would say, model to get on the right planet, 
then cut and measure, then talk to me.

Two other things work against what you propose. 1) Hams use skywave. 2) 
Horizontal wire and horizontally polarized radiation are two different 
things.

A horizontal end to the quarter wave only puts out purely horizontal 
polarization broadside to the horizontal.  Off the ends to sky wave angles 
it ADDS to the vertical polarization, an effect that would hardly be seen 
with 5 wavelength separated like antennas. "Increasing received signal" is a 
quite fuzzy statement that needs to be carefully qualified in order to map a 
model to it. Even then in real life the vagaries of real dirt in the quarter 
mile radius around the vertical, and the radial system itself will swamp 
many times over any theoretical differences between one or two 1/8 
wavelength "tails" at the top of the vertical seen from many miles via 
skywave.

I would suggest that the "hang-ability" and maintainability of an antenna in 
an L or T configuration at a given ham's site far outweighs any theoretical 
difference suggested by the models. And overall for performance, it's still 
radials, radials and radials.

73, Guy.