[Radio Wrangler]

Now that's interesting. It's a 2:1 ratio step-down

I'd have used a step up into a resistive load and a higher impedance amplifier to work as a current transformer and shunt resistor. This would make a low impedance load for the anode because Gm is supposed to be a parameter at fixed anode voltage.

Primary and secondary windings seem to be the same gauge of wire from Martin's photos. So it looks like the primary has twice as many turns as the secondary, it is also wound outside the secondary, increasing its length (and hence resistance) to over double that of the secondary. This is also the reverse of what I'd expected.

No mention of inductance or saturation current level is made. It would be easy to design a transformer that met those specs but which wouldn't work in the actual application. So I think that isn't really a spec, but just some tests to see if a transformer has failed for repair purposes.

David