Here are some spectrum photos from the tune signals of both FLDIGI and WSJT-X 1.8. All three are essentially identical showing some low level sideband noise +/- 30 kHz and down > 60dBc. There's no apparent difference in the spectra between pumping and non-pumping ALC, as Wes reported. http://www.pbase.com/brhunt/spectrum_photos Enjoy! 73, Brian, K0DTJ