This exhibit is a PCF80 with white lettering and a date of June 1974 showing how long this valve was current production.
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. The Band III service was the start of commercial television.
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 triode on the left is separated from the pentode by an electrostatic shield plate.
The pentode grid axis is at right angles to the triode and through the holes in the anode the suppressor support rod can be seen.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 47 mm tall.
References: Data-sheet & 1040. Type PCF80 was first introduced in 1953. See also1953 adverts.
