Cecil Moore wrote:
The T and the 1/4WL vertical
have about the same performance if the T's vertical
section is not too short.
--
73, Cecil http://www.w5dxp.com

The closer to a 1/4 wave for the combined vertical
plus top hat wire , the better. You can even improve
farther as far as current distribution if you make it
longer. IE: 3/8 wave total length. That will raise the
max current point up into the vertical section more
towards the top, rather than the bottom. Course,
if you do this, you will need a cap to tune out the
reactance. Like Roy says, the hat radiates little.
Even just two wires is a pretty clean vertical pattern with
little radiation from the hat unless the total length
is so long as to place the current max at the apex
or into the horizontal wires . So I wouldn't get too
carried away with the total length past a 1/4 wave
if I wanted a strictly vertical pattern. When I ran both
an L and a T, the L would often do better at close to
medium distances in the early PM. But the T was
usually better once it stretched out a bit. So most
of the time, I preferred the T. At that time, I also had a
Z dipole, which was better for NVIS than the L.
Now all I have is the "coax dipole" T. I did away with the
others.. The Z dipole was generally the worse of the
three as far as DX. Course, I don't work too much DX
on 160m. I can't hear most of them with my micky
mouse receiving antennas... :/ I've heard W8JI working
stuff that didn't exist here on my radio.. I've pretty
much faced the fact I won't be having a killer 160 setup
until I can get out in the boondocks.
MK