My 8640Jr has 5 total bands, covering 850 Khz – 31 Mhz.
I took some measurements with the Bandspread Control in the Maximum, Minimum and Midpoint of its range.
I started with the VFO output frequencies, as all of the other bands are arrived at by dividing these frequencies down.
With the Bandspread Capacitor set to Maximum, I had a range of 13.6 Mhz to 27.858 Mhz.
Next, I set the Bandspread Capacitor at Minimum. It is clear that this affects the high end of the range much more than the low end.
Finally, I set the Bandspread cap to the approximate center of its range, and made more measurements.