Hi Mark
The Radiola Model 46 is a TRF receiver. Each of the 3 #24 tubes are tuned to the same frequency. The schematic is in Most Often Needed 1926-1938 Radio Diagrams. It will also be in Rider Vol. #1. Check the plates of the 3 section tuner to see if they are touching. At the higher frequencies the tuner is open and it closes as you tune lower.
Norm