Harry7 wrote:
Both of these designs are of the Balanced L or Double L variety. Both
require a balun at the input to convert the 50 ohm unbalanced output
of the transmitter to the balanced tuner & feedline. You still haven't
gotten away from the main cause of inefficiency & power loss which is
the balun. [see http://www.somis.org/bbat.f1.jpg]

The best way I have found to tune a balanced antenna
and feedline system, especially at high power, is at:

http://www.w5dxp.com/notuner.htm

The balun always sees a purely resistive differential
impedance between ~35 ohms and ~75 ohms. A 1:1 balun
with a choking action of 1000 ohms will virtually
eliminate conducted common-mode currents. Symmetrical
placement of the feedline to the antenna reduces
inducted common-mode currents. The needle on the MFJ
current meter barely moves on the most sensitive scale.
Under these circumstances, a w2du balun is not lossy.
--
73, Cecil http://www.w5dxp.com