I finally got around to putting my new MFJ-1786 on the YouKits Antenna Analyzer to see the bandwidth properties with my own eyes.
In the video are two trace lines. The one that looks kind of V-shaped is an impedance curve. The other trace is the one we’re interested in. It appears pretty flat across the upper portion of the display with a deep notch in it. The notch is so narrow that it is easily missed until I make it move by making adjustments on the MFJ loop controller box.