Frequency	n/a (rotator controller)
Bands	n/a
Power	A universal digital rotator controller (replaces the OEM control box). No RF. Drives most amateur rotators via configurable motor voltage and position feedback.
Modes	n/a

Connectors

rotator	rear terminal strip to the rotator
computer	RS-232 and USB
power req	AC mains.

Universal - configurable for nearly any rotator ever built Point-and-Shoot knob plus CCW/CW controls and computer control Precision heading to 1/10 degree; up to 720 degrees over-travel PWM variable-speed with start/stop ramping to reduce stress RS-232/USB computer control; master/slave for stacked arrays No soldering to configure - jumpers plus software

Strengths

Works with almost any rotator; smooth ramped variable speed; precise headings; excellent computer control.

Weaknesses

Premium price; replaces (not augments) the OEM box; setup requires configuration.

Verdict

The gold-standard aftermarket rotator controller - the RT-21 turns almost any rotator into a smooth, precise, computer-controllable system.

The Green Heron RT-21 is a universal digital rotator controller that replaces the OEM control box and drives nearly any rotator, with Point-and-Shoot tuning, 1/10-degree accuracy, PWM ramped variable speed and RS-232/USB computer control (plus master/slave for stacked arrays).

Add a computer interface like the Yaesu GS-232B, or the board-level Rotor-EZ.

Green Heron RT-21 (Universal Digital Rotator Controller)