I have included a web-retrieved copy of the RadCOM G4DDK-004 article for completeness; though I'm working on a fractional-N PLL/Synth to produce the require 2556MHz LO.
G3WDG 3cm Receive Converter Build manual (3.7MB)
G3WDG 3cm Transmit Converter Build manual (4.4MB)
G4DDK 2-2.6GHz Oscillator/Multiplier RadCOM article - Aug 1990 (1.6MB)
Last updated: 20190426