The PCF805 is identical to the 30C18. It is a purpose designed oscillator and mixer for frequency changer use in VHF television receivers. Although there are two separate electrode systems in the envelope the cathodes are joined together. To lower cathode lead inductance two pins are used for the cathode connections.
The triode is on the right and the perforated sheet on the left is a screen with the anode within.
Screening is also used above the top mica.
The pentode screen is shaped and the triode anode can be seen on the left.
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 PCF805 was first introduced in 1962.