Posted by wayne burdick on URL: http://elecraft.85.s1.nabble.com/KX3-having-a-PTO-tp6438460p6438511.html
No. The VFO A knob is connected to a high-quality optical shaft
encoder whose position is read by the KX3's microcontroller. The
frequency of operation (down to the nearest Hz) is then sent to the
synthesizer.