The 6G5 (6U5) is a Magic Eye tuning indicator where the size of the shadow cast onto the bowl depends on the AGC voltage derived in the receiver. The AGC voltage is amplified by the remote cut-off triode and the anode voltage of the triode directly modulates the display.
The Raytheon Brand Label. The 6G5 Type designation appears within a feint circle on the opposite side of the glass. This is just visible on the full sized version of the main picture.
The triode amplifier electrode assembly is mounted centrally in the envelope with the display above.
The display bowl. The control element is the flat strip in the lower part of the opening. The helix around the cathode increases the life of the display.
The classic envelope is 38 mm in diameter and, excluding the UX6 base pins, is 88 mm tall.
References: Data-sheet, 1043 & 1040. Type 6G5G was first introduced in 1937. See also1937 adverts.
