[morzh]

Now to the antenna coil L1. When checking magnetics, soon after started I found the L1 coil was open. Simply by ohming out antenna to GND.

Now, this is how it looks.

   
   

As you can see, the winding is kind of "Universal", but wound with flat 5-filamet (or maybe 6) wire.
I am not sure what happened to this coil, it is open and considering it has a few filaments, all 5 or 6 of them have to be open.

This is what I see:

   
   

Considetring there are several filaments, I do not think there are many turns there. And I am pretty sure multi-filament flat wire could very well be replaced by litz, which is what RCA was, I think, trying to do. Maybe they did not have litz. Who knows.
But I cannot make "Universal" winding: it is a skill if done manually, and I do not have a tool and am not about t obuild one, as a couple of books suggest.

This is a strictly BC radio, so I am not sure I need to try to reduce inter-layer capacitance greatly, which what Universal winding is for, and litz will take care of whatever skin effect they were trying to deal with.

If anyone has better ideas, I am all ears.

Of course, there is always waiting for a parted radio popping up....

(speaking of which....I will try to look in Oldradioparts, Play Things Of Past. Who knows.....).

PS. Last thought, this is the antenna input coil. It is not, strictly speaking, a tuned coil. The second half is, but the first is not. So if I just make a reasonably similar coil out of litz (same N, and roughly the same geometry), it just might work...