[Arran]

R.G;
These sets would have used a long wire antenna, I think there were some loop antennas available in the aftermarket, but unlike a 1940s era AC/DC set they were never integral to the front end of the radio. Sets with Neutrodyne circuits are a sort of improved TRF design where they have an extra winding that feeds a small amount of negative feedback to the input of each RF amp circuit preventing oscillation, so they have a higher gain then a straight three dialed TRF set, that was until they introduced screen grid tubes in the late 1920s. It's basically to neutralize any positive feedback that can cause the circuit to go into oscillation, before that they had to use a bypass condenser or reduce the gain of the circuit.
I would like to get my FADA going again someday, the only part missing is the cabinet, and one of the audio transformers is open. To this day I'm not sure whether it was a 175A or some other model, or whether it was a table set, or was pulled out of a console model. However I am reasonably certain that it was sold in Canada as it has a set of mid 1920s Canadian Westinghouse branded tubes, with Bakelite bases.
Brass based tubes were not around for long, likely due to cost, and I suspect that most of those produced were 201s not 201As, 201s had 1 amp filaments and were hard on A batteries. If you can't find 201As 6C4s can be used as a substitutes, for testing purposes, or if you like making adapters. The biggest issue with 201as, as with any other early tube, is that the solder in the pins often goes bad, so if you have a weak 201A, or one with an open filament, try sucking the old solder out and resoldering the pins, they don't usually fail unless abused.
Regards
Arran