Thanks Martyn. Hopefully it'll be an option available in some future version. For the moment I'll just input each frequency manually in the signal generator dialog. The reason I would like to automate this somewhat is that I use the spectrum mode to scan for harmonics, but would like to zoom/narrow in on each harmonic and analyze the signal. If I could use a "hotkey" to step through the frequencies in the harmonic area, that would simplify my data gathering. The 10 Hz step is a little too broad.