The PCC84 and PCF80 both featured in set-top converters for the new ITV television Band III channels that commenced broadcasting in 1955. The transmissions were on around 170 MHz and much higher in frequency than the BBC Band I signals at around 50 MHz.
This PCC84 is a later product as 1950's production would have been UK based.
The PCC84 was specifically designed for cascode operation. The normal configuration was for triode one to be operated as a grounded cathode stage directly coupled to triode two. Triode two was connected as a grounded grid stage.
The triode has a smaller inter electrode capacitance than a pentode at VHF and could be made physically small. The photograph shows that within the envelope the electrodes are a small percentage of the total volume. The two triodes would be used for initial signal amplification at up to 350 MHz. The low anode voltage and relatively high current being features to ensure low noise operation. The anode dissipation was 2.0 Watts for one triode or 2.5 Watts for both triodes operating. See alsoPCF80 for the corresponding oscillator and mixer.
The two triodes and inner screens.
The screening arrangements differ for each triode.
The thin glass tube envelope is 21 mm in diameter and excluding the B9A base pins has a length of 48 mm.
References: Data-sheet & 1040 Type PCC84 was first introduced in 1953. See also1953 adverts.