NT88

This could be the Admiralty code for the developmental CV14 silica transmitting triode. It was intended for a 240 MHz radar set. Likely the tube originated experimental variants XL and XN. According to Foley it never came out of the experimental phase and was canceled in 1942.

The PRO AVIA 7/715 file reports the output curve for the variant XL. A single tube operated as oscillator at 20 kV pulses generated about 300 kW at 100 MHz, but output dropped abruptly approaching 200 MHz.