No wonder they lost the war! The simplified schematic still poses several questions, first what is going on with the last IF and detector tube cathodes? Looked and there is no DC path to ground, maybe because they stuff -50 volts via that 100K resistor onto the plate of the detector and depending on the level of the incoming signal that negative voltage is passed thru to the cathode and that’s the return path for the last IF amplifier tube? Think I have seen something like this in the old Soviet USP receiver where it servs as a form of squelch and limits the radio to only picking up the strongest signals? Overall gain control is by raising or lowering G2 voltage on the last IF amplifier and 1^st RF, something like the German Torn EB but that’s a TRF set and what the hell is that triode and T1 after the HFO doing being coupled into the BFO and G2 of the first IF?

Figure that S1 is the send receive switch and if the detector is also a squelch removing the HFO is more than enough to mute the receiver in transmit and the switch across VC (20) kills the BFO but still allows plate voltage to be available to the T1 triode mess and VR is the overall gain control. The real question will be if you get this radio up and running is about the detector and last IF and if that is a type of squelch or noise limiting system?

Ray F/KA3EKH