"John, N9JG" wrote in message
t...
Since my original posting I have learned that the Commander HF-2500 uses
Eimac 3CX800A7 triodes, whereas the QRO HF-2500DX uses Svetlana
4CX800A/GU746 tetrodes. Some sources have stated that the IMD figures for
the Eimac triode in a grounded-grid configuration are better than the
Svetlana GU746 tetrode in grounded cathode grid-driven mode.



John,

IF I remember the old web sites both companies had a few years ago --
shortly after the split --
one took the TRIODE route (Commander) the other (QRO) the TETRODE route.

The rest is amateur radio history!

gb