Developping with 4nec2.
The antenna caracteristics as calculated with 4nec2, feeder impedance 110 ohm to simulate the 75 ohm 1/4 wave stub.
75 ohm stub winded to form a choke balun, 3.52m of RG 59.
Antenna in portable opartion, I was received 579 in North Carolina with 40W.
Antenna supported by a 12m fiberglass mast and nylon rope.
Each side is 5.34m, which means the loop is 21.36m.
Actually the antenna is much more wide than simulated,
the S.W.R. meter of the TS-480 indicates 1:1 from 14.000 to 14.350
A very performant low-noise antenna!