[Milsurplus] Mallory Inductuners... was CV-253 & APR-1/4

[J. Forster]

With thanks to Robert, I just got a schematic of the CV-253. Turns out, it
uses Mallory (style?) Inductuners...  flat, helical coils on a bakelite
substrate with a wiper that progressively shorts more and more of the
winding as the shaft is rotated.

I've only seen these puppies in the GLR-9 and the civilian version the ACL
SR-209. They may also be used in some of the W-J and/or CEI ELINT
receivers of the early-mid 1950s.

Does anyone know of any earlier use than the CV-253? I cannot remember
anywhere else they were used in tube circuits, either.

Also, since they have a wiping metal-metal contact, they seem a poor
choice for a scanning receiver because of wear. Any experiences?

Curious,

-John

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