Articles and Designs from Mr Laurie Baine  VK3SJ
Mr Baine is a self taught radio engineer of very high calibre whose principal interest is the design and construction of medium to high power AM Broadcast transmitters . This interest is made manifest by some very interesting amatuer radio construction activities of which I have seen many excellent examples.  Laurie is not confined by the narrow strictures of orthodoxy and is allways prepared to push the boundary and shake the trees to see what falls out.  

With his most kind and generous permission,  I present here are a number of his designs that he has consented to share with the radio amatuer  fraternity  with the hope that it inspires similar efforts  and thus show what is achievable.

Laurie has shown me a number of working prototypes of various high power modulators. Most intriguing is a switching modulator of very tiny form factor. Switching designs are less readily reproducible by amatuers due to the difficulty of satisfactorily handling high level switching currents.  The Progressive Seris Modulator was designed to address the difficulty that the amatuer may have with a switcher.  It works on the simple principle that the unmodulated carrier power need not be supplied by a linear system that must
otherwise thermally and uselessly dissipate 50 percent of all that DC energy that you went to such time effort and trouble to create.
Power is only dissipated by a Class B system  , but,  only in the act of actual modulation.  Otherwise, when providing the unmodulated carrier power, this modulator is "100%" efficient.

Now also presented is his proven design for a pulse width modulator.

A high level, high power modulator for AM solid state transmitters in the 100W-plus class
Design  by Mr Laurie Bain VK3SJ  2014
Artwork for a PCB will be made available later.

A high power class D transmitter for the 40 Meter Amatuer Service
Design  by Mr Laurie Bain VK3SJ  2014

A high power  pulse width modulator for solid state class D AM transmitters
Design  by Mr Laurie Bain VK3SJ  2014
Laurie has not written of made available to me a written description of his design.  Perhaps if I ask, his description will appear. I have seen the made up boards and heard the on-air signal which is crisp, clean and beautifully modulated as recieved at my location over a very unfavourable path for 160Meters.

Page created on Mon Mar  2 18:06:20 EST 2015
added pulsemod  drawings.  Tue Mar  3 18:16:11 EST 2015
replaced  modulator-progressive schematic with Laurie's "final version" Wed Apr 22 11:31:44 EST 2015