But Uwe,

With a 100m Vertical you  reach 1W ERP with 20W TX power! So 1,2kW will
be 60W ERP on 137kHz ;-)

If you think about the ratio between achieved signal to the effort you
have, this may be an alternative ;-)

73, Stefan


Am 03.03.2010 12:26, schrieb Warren Ziegler:

 Uwe,

       I use a loop for transmitting on 137kHz. the loop is made up of
 coaxial cable with 2 turns in parallel spaced 3 meters apart.
 The loops are approx. 24 meters vertical by 44 meters horizontal dimension.
 With 1200 watts of transmitter power output, I achieve an ERP  of 4
 watts (measured).

     The tuner is built to withstand high currents and voltages.
 I have had several small fires when wires were too close together.