Small, cheap and widely available chinese transformers are frequently used in digimode interfaces, however the documentation is very poor. Both primary and secondary consists of 800 turns of enameled 0.06 mm copper wire wound with double wire. It has DC resistance of 135 ohms +/- 20% and inductance of 290 mH +/- 20%, wound on a EI14.5MM core of 6,5 mm thickness. Other data as pictures:

AF XFMR 1

AF transformer

Dimensions (mm):

Dimensions

PCB footprint (dimensions in mm):

Footprint

and Kicad module download here.