[Boatanchors] Modern AM Modulation techniques

[Dennis DuVall]

Ninety per-cent efficient maybe but got no soul….  :^(

Dennis D.  W7QHO
Glendale, CA

*************

> On Oct 5, 2015, at 9:30 AM, Rob Atkinson <ranchorobbo at gmail.com> wrote:
> 
> All of the AM medium wave broadcast rigs are solid state with class D
> RF modules producing various power levels that are stepped on and off
> by a streaming binary coded signal derived from an A to D circuit
> sampling the program audio.  This is fed to a logic board that steps
> on and off needed combinations of RF modules that are paralleled with
> each other to provide the needed RF level at any instant.  A 50 KW rig
> will have 50 to 100 modules, each using two FETs in power blocks of
> 500 to maybe 2 KW.  The modules are hot swapable.   Harris can make
> rigs up to one or two megawatts by simply building bigger boxes with
> more FET modules.
> The master mind for this design was now deceased Harris engineer
> Hilmer Swanson.  These rigs are about 90% efficient.
> 
> here's a brief description of how it works:
> 
> http://hawkins.pair.com/wabcnow.shtml#digmodsect
> 
> 73
> 
> Rob
> K5UJ
>