Here are some improvementes made on this still fine RF amplifier
It uses 1 tube 3cx800a7 triode with all the circuits needed for a reliable work even if the project is almost 20 years old.

Two features have been added :
1) blower speed reducer with timer
2) grid protection visual indication

The first feature has been added due to the blower that after so many years of work has become noisy.
This continous noisy presence of the rotating fan did not let me concentrate at the band listening,
specially when the PA is in st.by for long time.
Its job is simple: during TX the blower runs at maximum: when the PA goes to St.by the timer let it run still 1 minute or so, before reducing the speed via a regulated dimmer. The dimmer is not critical :any filtered brand with external potentiometer is OK.