I did a detailed signal analysis of the Langrange-4 datasets with baudline and posted it to my blog. The target is the Sun-Earth L4 position at the 1420, 2008, and 3991 MHz frequencies. Found many interesting signals. Some with modulation characteristics. Several demo videos too.
Some previous discussion about the strange Lagrange-4 3991 MHz signal:
It is some sort of wideband modulated signal with a ∆1267.226 Hz spacing between tones. The 3991 MHz is further analyzed and discussed in more detail and here:
Here is a plot from the date of the signal collection showing that NASA's STEREO A & B probes were approximately at the L4 and L5 points.
It is still a mystery how STEREO's 8.4 GHz signal could get down-converted to 3991 MHz by the ATA. Maybe it is some sort of sideband / distortion / artifact? Any thoughts about this?
As far as I can tell there is no way to tell what the actual center freq is on data sets so maybe it is a typo. I thought it would be automatic but I guess someone has to type it in. It seems the bytes that are supposed to tell you are all the same no matter what data set you look at. When I tried to read the bytes the way rob explained it always returned 1413.4464.