Sensibly equivalent¶ to:
The UBF80 features a variable μ amplifier pentode and a pair of diodes in screened envelope. This suggests use as a final IF amplifier with the diodes for signal and AGC rectification. The 100 mA heater requirement was to allow for operation in receivers without mains transformers, the so called universal sets as they could operate from DC mains as well as AC.
The valve in close-up shows that he grids are visible through a hole in the screen and anode.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 55 mm tall.
References: Datasheet, 3002 & 1040. Type UBF80 was first introduced in 1950.
Absolute Maximum Operating Conditions¶
Updated February 04, 2013.