My opinion - hope that is OK. This whole concept seems like an awful waste of power and certainly will stress most amateur grade components
Merry Christmas, Al
I agree.
I think the reason it has obtained a toehold at a few AM broadcast stations is that they are in bad shape economically and are desperate to reduce their power bills. Thus the 50-kW station using such a system is 50-kW only during pauses in speech or other programming. During full modulation, the carrier drops down to 12.5 kilowatts or so. That really saves on the power bill.
Of course, they'd save even more on the power bill if they just used standard AM and dropped down to 12.5-kW steady carrier. And it would sound better too, and be much easier to implement.
But... the FCC says that you must stay within 15 per cent. (if I recall correctly) of your assigned carrier power. If you don't there are fines and penalties. And they might recalculate your protection from other stations if you apply for a power cutback.
So the "reverse controlled carrier" operation lets them save power and still pretend they are running 50 kilowatts.
73,
Kevin.