The NR64 naval receiver valve is a variable μ amplifier pentode. This suggests use as RF or IF stages in an AGC controlled superhet receiver. The control grid connected to the top cap reinforces this view.

The classic envelope is 36 mm in diameter and, excluding the IO base pins, is 104 mm tall.

References: ¹⁰⁴⁰ & ¹⁰⁴³.

 
Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	m	h	a	g2	g3	-	h	k	g1

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	100	-3	8.0	2.7	0.46M	2.9