Sensibly equivalent¶ to:
78E A678 AG78 CV2544 G78 UZ-78 UZ78
The 78 and 78E are variable μ RF pentodes. This exhibit has no manufacturers name, just that it was made for the US Navy.
The RCA Receiving Tube manual describes the 78 as being electrically identical to the IO based 6K7 apart from the capacitances, thus this is one of the Magic Three valves.
Thanks to Peter for identifying the CKR on the base as the abbreviation for Ken-Rad.
The sheet screen obscures the electrodes.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 96 mm tall.
References: Data-sheet, 1040, 4055 & 1043. Type 78 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated April 03, 2014. shape:classic construction:pinch type:pentode age:1930.1940 base:ux6 heater:6.3v pins:6 pin:1.h pin:2.a pin:3.g2 pin:4.g3 pin:5.k pin:6.h pin:tc.g1