[EdHolland]

Jayce,

I have been researching this very thing. The can is an antenna coupling transformer. Kolster-Brandes adopted anti-interference methods that became popular in the mid 1930s. The antenna had a transformer which created a low impedance balanced output. This was fed down a (sometimes) shielded twin line to the radio, helping to avoid noise pickup in and near the house. Another transformer at the radio "unbalanced" the signal and transformed back to high impedance for its antenna circuits. Kolster Brandes sets around that time featured the system, branded "Rejectostat" as yours displays. Kits could also be purchased to adapt other radios.

Hope that is of interest,

Ed