I have been following this thread with much interest. Learning more about 160 meter antennas thanks to you guys. I am planning a 160 meter inverted L or something similar myself. Looking at ON4UN's book I noticed a T configuration also. I can manage a 160 meter L or T which would be 75 feet vertical and then one horizontal wire or two horizontal wires in a T. The horizontal wires would
have to slope down about 45 degrees. I am trying to figure out the length of the T horizontal wires,
(presumably shorter than the L wire) and the advantage if any of the T top loading compared to the L
If a T is used the top -loading wire, the horizontal (high -angle ) radiation from this top wire will be effectively canceled in the far field.
I believe the T is a more effective DX antenna than a L .
But a lot comes into play. Radials - Radials - Radials besides other things. I think at lest 65 radials should be used on a ground mounted vertical T . Mine now has 115 -130 foot radials.
How long the top wire ? My T is 64 foot vertical and the top wire is about 45feet 8 inch on each side of vertical section
Xs=0 at 1.835 I made it a little high.
If ground mounted and if you use radials on the ground the Top Wire is adjusted to find the Xs= 0 or resonance freq.
I would suggest you put your radial field in place before you build the T. If you build the T then the radial field , things will change on you.
If you use elevated radials then the Top hat is the missing portion of the vertical plus a % or the equal of the other half as I recall.
The Xs=0 is obtained by adjusting the 2 radials and not the Top hat.
The Insulators at the end of the T or top wire should be very good . High Voltage is present at the ends.
For a discussion on the T verses the L go to Top Band reflector http://lists.contesting.com/_topband/2008-10/msg00041.html
I use a 80 meter band T vertical with 2 elevated radials and though I could improve it with a good ground screen below and perhaps 2 or more radials . I find the antenna is in general as good or better than the ground mounted 160 meter T. But the 80 T is elevated to 14 feet. And 80 meters is not 160 meters.
I have used a L and many many many hams use a L with good success on Top Band, they do work. From what I understand if you wanted to work more USA you might want the L over a T
But for dxing , I will stick with the T for now. The claim is a T receives better than a L . I have no clue . I use lots of Beverage antenna but then again the T does receive signals very good.
I am no expert on this subject but this my understanding of the antennas and experience I have had.