I have seen many examples of a diode in series with the B+ line from the secondary of the mod transformer to the PA tube. It was used in some HF mobile rigs and there is some mention of using a diode in very early BC transmitters back in the 1930's. What is the purpose of this single diode? Does it allow only positive pulses from the audio wave to the PA and at the same time eliminate the possibility of the negative part of the cycle from approaching 100 percent negative? Is the negative part of the cycle eliminated?
I know of circuits using three diodes for negative cycle loading and then there's the three diode keep alive circuit that I believe Steve WA1QIX developed?
Will the single diode application cause distortion? Any thoughts on this will be appreciated. I plan to build the QIX circuit for my BC-610D but will this cheap & dirty single diode do harm or good?
I am not an engineer so you smart fellers out there must have an answer