[Elecraft] Frequency display on P3?

[Frank O'Donnell]

Here's what I'm sure is a beginner question.

If I feed an accurate signal from a waveform generator into my K3S, on 
the P3 it appears right about 120 Hz higher than the actual frequency. 
This seems to be independent of the mode the K3S is in. What causes that?

I noticed this when I had my K3S/P3 running while working the ARRL 
Frequency Measurement Test with other gear, and was curious about it.

Thanks much,

Frank K6FOD