This triode pentode valve as designed for VHF frequency changer use for operation up to 220 MHz. This would be mainly for radio as television receivers tended to use the PCFnn 300 mA valves.The triode is the oscillator and has to produce 5 V pk-pk signal. The screened pentode is the mixer. The valve has two cathodes so two independent valves are housed in the one envelope. The two valves can be used separately if required.
