An AD9851 synthesiser was clocked by an Oscilloquartz 8663
10 MHz DOCXO purchased from "Zhou" in Hong Kong for less than
what a bottle of cheap Scotch would cost, and calibrated against WWV on
10 MHz. An Arduino Uno programmed the 9851 to generate 
137.555 x 16 kHz which was divided by 16 by a cmos 4020. This was to
improve the resolution and frequency accuracy.  The Uno also keyed the
carrier according to the op32 code that was provided via email
by DF6NM.  The keyed carrier, a messy 3v p/p square wave, drove 2/3
modules of a Decca amp running at 60 volts 12 amps to yield 3-1/2 amps
of RF which was coupled via 1.6mH of 2mm Litz to a 100m wire at about
12m average height.