The 3CX3000F7 are forced air cooled ceramic-metal power triode containing a thoriated tungsten carbide cathode of which the maximum plate dissipation up 4kW and are designed for used as RF power amplifier, oscillator, or modulator.
In order to simplify the installation of application at low-frequency,

GENERAL  CHARACTERISTICS
Filament Voltage                    7.5  V
Filament Current                    50.5  A
Amplification  Factor            160
Interelectrode Capacitance (Grounded Cathode)
Cin                      38.1 pF
Cout                    0.6 pF
Cgp                     24.5 pF
Interelectrode Capacitance (Grounded Grid)
Cin                      38.1 pF
Cout                    24 pF
Cak                     0.6 pF
Zero-Grid-Voltage Plate Current (Ua=5 kV)          440±80mA
Cut-off Grid Bias (Ua=5kV, Ia=1ma)               -45V
Operation Position                Vertical, base up or down
Cooling                                    Forced Air
Maximum Anode Core and SealTemprature         250
Maximum Height                           469.9 mm
Maximum Diameter                      105.7 mm
Net Weight                                     3.4  kg