interesting feedback in an old broadcast AM radio

I am restoring an old Kolster and Brandes radio from approx 1928. After partly rewiring the radio with cotton isolated wire as it was (the wire was completely detoriated), repairing the LF interstage transformer, it was time to draw up the wiring diagram
The radio had a tetrode RF amplifier, an A442 I suppose (or the 2 Volt equivalent) and a triode detector and triode final amp. I selected an A415 as detector and a B406 as AF amp.
The diagram is interesting, The grid of the terode has a tuned input circuit, the anode of the tetrode is loaded with a choke, a 1 1/2 inch diam coil that had very thin wire. How much, unknown, it was mostly gone. So I wound it with 0,2 mm wire, 250 turns.. The anode of the tetrode goes also via a cap to the grid of the detector. The regeneration feedback was via a small variable capacitor from the grid of the tetrode to the anode of the detector, so over 2 tubes.
The radio did work, but the gain was too high, I had to diminish the feedback quite a lot. But, the radio did work only for frequencies higher than 1 MHz. Below 1 MHz it was completely dead. I also had to damp the choke and the feedback was very uneven over the band.
I investigated a little more, and found that the diagram indeed was quite clever. The choke has to be bigger, the self resonance should be lower than the lowest frequency of the MW band. So the load of the anode of the detector is always capacitive.
Doing so, the regeneration feed back forms a capacitive voltage divider with the variable feedback capacitor and the capacitive impedance at the anode. That will give a wide band voltage divider. So I rewound the choke with the exptremly thin wire that was originally at the coil. Ending up at a resistance of approx 350 Ohms.
The radio immediately works very fine, hardly any variation of the regeneration feedback over the band and I didn't have to load the choke anymore. Like original. In the evenings I receive many stations at a 18 meter wire antennea, Venezuela, Cuba, Guatemala, Mexico , about all centro America. The radio is very selective, and that with only 1 tuned circuit!
The regeneration system has more in it as appears at a first glance!!!! VERY clever design.
Must be fun to try that design at 80 meters!!