Tried tuning in the TACAN station (CBU “Columbia”) at Portland International; presumably it’s there for the Oregon Air National Guard which flies F-15s from the airport. Navigraph showed the station’s frequency as 109.2 MHz, but to input it to the F-35A’s TACAN selector I had to convert that to the proper military-style coding, as “29X”.
Seems to work! I got both distance and bearing on my nav display, pointing back to the location of the beacon on the airport grounds as I flew around. 
