Having just read an excellent book about the DC3 in which great use is made of the manual DF tuning, that seems to be the most likely answer.
Sounds you are describing the ADF or radio compass box which among other knobs has a very small winding handle on some installations and is in the cockpit roof. That is used for manually turning the loop aerial for an aural null.
The large horizontal wheel you describe sounds more like the the manual rudder trim wheel on the DC4. The DC3 does not have that wheel but instead has a winding handle below the throttle quadrant and has a numbered scale. The Lockheed Hudson has similar style trim wheels as the DC3.
Unless the pilot has long hairy ape like arms, the DC3 rudder trim is not easy to operate accurately since the pilot has to lean down to see the handle and numbers and this can lead to distraction when flying on instruments. Worse still the aileron trim wheel is also under the throttle quadrant as is the autopilot engage handle.