From my copy of WE Transformers from 1964.
197B
Freq Range: 0.017 - 6000
Impedance Ratio: 75:110
Low Winding: (1-2)
High Winding: (3-4-5)* (CT)
Max DCR
Low Winding: 0.135
High Winding: 0.110
Inductance
Min: 450 millihenries
Test Freq: 0.1kc
For Winding: (3-5)
Shield: Electrostatic
Type: Repeater
Impedance Ratio (Ohms)
From: 75
To: 110
Frequency Range (cps)
From: 17
To: 6000
There's more info, but perhaps it would be better to send you the pdf.
Mark