The 6BQ7A is an all glass miniature VHF double triode and is internally screened.
The 6BQ7A would be used for cascode RF amplification, or possibly frequency multiplication. In the latter case the valve is operated as a non-linear (Class C) amplifier. This causes harmonics of the signal frequency to appear in the anode current. The anode tuned circuit is then chosen to resonate at one of the harmonics, usually the second or third.
This exhibit was made by RCA for Hewlett Packard.
The HP logo on the glass and within is the bright electrostatic screen between the triode sections.
A general view where the camera focus in the far wall.
The rest of the Hewlett Packard name and an acknowledgement of RCA as the maker.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins the valve is 48 mm long.
References: Data-sheet & 1040. Type 6BQ7A was first introduced in 1954. See also1954 adverts.
