I do have one of the old alliance units where the top mast passes
completeley through the rotor. It's in the attic turning a small log
pereodic for 2 and 432 by Elk Antennas. The knob has a line you can feel
so you can tell where you are in rotation. It has 36 steps around the dial
so you get 10 degrees of rotation for each click. It was new in the
box and over 20 years old when someone gave it to me 15 years ago.
Using a newer Channel Master digital TV rotor to turn a HF mini beam on a
push up mast. Can't tell where you are, but it's not hard to get there.
Box has red led display that a partial may be able to see. Remote
control allows you to enter a 3 digit beam heading. Box clicks at start
and stop of rotation. This was supposed to be a temp setup but has been up
2 1/2 years. A little trial and error and a little memory and it's not
hard to figure out where I'm pointed.
If I ever get the Ham IV reinstaled, I'll consider the Rotor e-z card
from Idiom Press. Allows computer control and turns the calibrate knob on
the control box into a pointer to allow manual rotation.
73 Steve KW3A