Over the last week or so I have been doing quite a lot of measurements myself. They also confirm that the MMIC ruins what is otherwise quite a good spectral output, and I am thinking about various ways to fix it.
So I would have been very interested to see Jim's video. Unfortunately though clicking on the link does not run the file.Evidently my browser does not know what to do with that extension. (I haven't come across it before either.)
Related to this; I discovered a long time ago that the chinese modules (and possibly the AD985x itself) generates a whole forest of junk at about -60dBm (ish) while it changes frequency, and for about a second or so afterwards. In any sweep mode it does this all the time of course!