The PCF80 is from the era of VHF Band III television. Band III television in the UK began in 1955, up to that date the only program was the one BBC channel in Band I. The Band III service was the start of commercial television and the move from 50 MHz to 175 MHz.
The valve is a triode pentode, with separate cathodes, designed to function as a mixer and oscillator in the tuner.
The article referenced above gives details of the faults and performance of the PCF80.
The local oscillator triode on the left.
The mixer pentode. The suppressor grid support can be seen through the holes in the anode.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 48 mm tall.
References: Data-sheet & 1040. Type PCF80 was first introduced in 1953. See also1953 adverts.
