I have now worked out that the term AntennaTuner= is the correct file entry, not Tuner= as the hep text says when clicking on the ? in the settings tab. Having aded AntennaTuner=AC002; to the cat ini file. The tuner now works for for the FTDX101MP. Note I did not add AC001 first as my antenna tuner is always switched on. It could be you have to send that command first to turn the tuner on.