Question About Class E Transmitters


Bobby Drummond
 

I may have asked this question before of the group, but I don’t think so. Here goes:


Is is possible to design a workable Class E transmitter final using a tube for the final amplifier?

I ask this because almost all of the homebrew gear that I build is tube type since I have saved some tubes from my stint as an electronics technician during the 1970s (and collected some more tubes over the years).

Tube finals tend to be much higher impedance devices than transistors or FET final amps and have higher load resistances, but I still wonder if it is possible to craft a workable Class E tube type transmitter via paralleling tubes and using tubes with low plate load resistances.

Anyone on the list got any ideas or feedback about this subject?


73 de Bobby D - AK4JA


nm0s_qrp
 

There have been very few articles about tubes in switching applications.  The challenge with using a tube is that when the tube conducts large cathode current at low plate voltage, the grid and screen currents may become large enough to cause damage if not controlled.  Otherwise, there is no need to parallel devices, just use a pi network  to perform an impedance transformation.