[Milsurplus] mechanical modulator

[J Forster]

At a guess, there was an inductor as part of the RF circuit, and a
winding on that inductor carrying the 60 Hz. sweep current. The 60 Hz
would partly saturate the RF inductor, varying its incremental
permeability, and hence the RF operating frequency. Sort of like a
magamp (magnetic amplifier).

Best,
-John

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Hue Miller wrote:

> Those sweep generators from the 1930s-1940s, how
> did they generate the sweep? They had some kind of
> inductor winding at 60 Hz mains supply, but i cannot
> recall how this was coupled to the RF LC circuit.
> -Hue K7HUE