Green Heron RT-21 Rotator Controller

  • Rotator controller with integral PSU
  • PWM speed control effective for most rotator types
  • Precision ramp control for smooth starts and stops
  • Manual control using CCW and CW buttons
  • Point and Shoot knob for set and forget operation to 1º precision
  • The ability to correct for mast slippage using OFFSET
  • Computer control via RS-232 or USB to 1/10º  accuracy
  • Precision heading accuracy up to 1/10thº

Price excl VAT: £545.00
incl VAT: £654.00


The Green Heron RT21 is a rotator controller with a difference. The unit has an integral power supply. The bright clear display shows current heading  and manual target heading. Moving to a different heading is easy – either use the CW/CCW buttons or, in reality, the far better way is just to turn the manual ‘point and shoot’ knob to the heading you want – the desired heading is displayed on the display – then just let go and it does it all for you.

The RT21 ramps up the rotator PWM at the start (adjustable) and ramps dowm at the end of the movement so no hard stops and shock loading of the rotator.

If you have a SPID rotator then you will know that one of the limitations of the standard SPID controller (Rot1Prog) is that you are limited to a maximum of 16V supply as you need to power the controller and the rotator from a single source. With the RT21 you can now power the SPID rotator at the full 24V it is capable of – this results in faster movement, higher torque and less sluggishness when the weather is cold and turning torque needs to be higher to overcome cold grease and stiction.

The RT-21 is a universal digital rotator controller that can be user configured for motor voltage and position feedback.  Configuration is accomplished by a combination of PCB jumpers and software settings, no soldering or major disassembly is required.  This flexibility allows the RT-21 to operate any commercial amateur rotator being built today, and virtually any rotator ever built.  In addition, there are configuration settings that allow custom control for commercial and industrial systems.

We can supply the controller pre-configured for your rotator – just tell us what you have when you order.

  • Off-white chassis and front overlay, black cover
  • Bright LCD with variable intensity yellow-green backlight.
  • Front panel CCW and CW controls, Point-and-Shoot knob, and computer control
  • Integral 220-240C Power supply
Why upgrade your controller?

In addition to simply running your rotator or changing to meet your future rotators, the addition of an RT-21 will add modern functionality to your rotator:

  • Adds USB and/or RS-232 control
  • Adds high resolution digital display
  • Adds Point & Shoot hands off operation
  • In most cases, improves heading accuracy
  • In most cases, adds PWM speed control and gradual start’/stop to your system eliminating tower and rotator stresses

The RT-21 manual contains separate pages detailing the setup, hookup and calibration of 14 of the most common rotators in use.  Additional resources are available from Green Heron in the form of applications notes, that detail less common or custom requirements.  In addition, we have developed experience and have documentation on many older rotators and custom requirements.

Common Rotators Supported and Documented in the Manual:
  • Hy-gain HAM series, T2X and HDR-300
  • Create RC5 series
  • Yaesu All models
  • Orion 2800 and 2300 models
  • TIC RingRotor
  • Prosistel
  • Alfa-Spid (runs the rotator at 24V for full torque)
  • Alliance HD-73
  • Rotor Doctor (CATS)
  • Diawa MR-750/MR-300

2 in stock

Rotator Type