In my original email I asked if the 39-389 opener would work on my 1960 version of the Andersen window. Notice the distance on the tape from about the center of the swivel gear to the end of the operator arm. It looks to be about 17". When I measure the total distance between the knob on the left side and the knob on the right side that connect to the window that distance is 34 1/4" . Let me know if you think that your awning window operator will work with my window. If the operator is a little shorter and opens the window a little less that will be fine.
Thanks in advance for your help.