antenna coupler help for medium waves?
 

i have a transmitter 50 ohm output at 1431khz medium wave band. my antenna is an inverted-L antenna with (5/16)*wavelenght total lenght (20 meters
vertical and 45 meters horizontal wire 2,5mm). i have 3 scematics for antenna coupler system. The first and the second
schematic send me 2 radioamateurs. I calculate the third coupler with 4nec2 software. Which coupler is the best
for my antenna??? do you have to propose another schematic?
i have a variable capacitor 500pf and a variable coil about 100uH. thanks

http://www.sv9cvk.gr/images/KWcoupler/COUPLER.jpg
http://www.tzitzikas.webs.com/match.JPG
http://www.tzitzikas.webs.com/4nec2.JPG