Steve,
The turns ratio of T501 from primary to secondary is higher if you build the radio for 9v instead of the more typical 12v.
That higher ratio means a 9v build running on 9v has about the same power out as a 12v build on 12v.
The turns ratio of T501 is the only difference between a 9v build and a 12v build.
The first thing to blow if you exceed the recommended power supply voltage (9v or 12v, depending on build) is the BS170 finals,
as they will be working too hard.?
Everything else in the radio should be fine at a somewhat higher power supply voltage.
?
The modulator at Q507 can be used to reduce power, such as when adjusting an antenna tuner.? Q507 is a linear voltage regulator that adjusts the voltage to the BS170's as a function of DAC signal coming from the STM32F processor.? It can only reduce the voltage to the finals, it cannot increase the voltage to the finals above that of the 9v or 12v power supply that you provide.
?
Jerry,? KE7ER
