The PCF80 is from the era of VHF Band III television in the UK that started in 1955 with the introduction of Independent Television. The BBC had a single channel at around 50 MHz whereas Band III was three times higher in frequency.
The valve is a triode pentode, with separate cathodes, designed to function as a mixer and oscillator in the tuner front end.
The triode on the left with the pentode mounted at right angles and taking up most of the volume.
The triode grid with the winding reflected off the rear wall of the anode.
There are heat-sinks on both sections and the pentode is screened at the top from the triode grid supports.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 49 mm tall.
References: Data-sheet & 1040 Type PCF80 was first introduced in 1953. See also1953 adverts.
