How to add an RF protection device to amplifier?

[KA2QFX]

Tom,
You still have a problem. Steve's board is a wonderful circuit but as I recall is tracks the current vs. voltage from the modulator stage. If either one falls out of the comparator window the circuit "trips".  I suppose you could compare final PA current to a non-varying reference voltage if you reduced the sensitivity of the comparator. A question Steve could easily resolve.


But you still need a way of detecting the reflected power and something for either condition to act upon to shut-r-down.  Speaking of "r". Did you name this contraption yet? 

Mark 

[K1JJ]

Mark,

Good point about the current vs: voltage tracking.   Yes, maybe if the Voltage is set to a certain threshold value, the current will hit the desired preset point and trigger the comparator. I think that wud work, but Steve wud know for sure.  I need a trigger at above 10A at 30V.

The LP Filter has a reflected SWR output, so I'm all set there.

I plan to use the overload hi or lo to trigger a SS device to shut down the amplifier bias or PTT circuit voltage.  No relays involved.

T