I tried the stepper with the 25:1 gears on the mag loop and it drives, but not on the 9V power supply. 24V is ok.
This is the notch seen on the nano VNA.
But, the stepper driver featured earlier generates a lot of hash. That is aggravated by me running the stepper motor over around 10M or so if CAT5 cable.
I'll try again with a non PWMed driver.