For a 1.5 m radio dish, the best motorised mounting depends on how accurately you need to point it and whether you want full sky tracking or just the ability to point to a fixed direction. There are three practical approaches used by radio astronomers:

1️⃣ Alt-Azimuth Mount (Most common for radio dishes)

This is usually the best and simplest solution.

How it works

• One motor rotates the dish horizontally (azimuth).
• One motor tilts it up/down (elevation).

Typical hardware

• Heavy azimuth bearing or turntable
• Linear actuator for elevation
• Two stepper or DC gear motors
• Controlled by Arduino / Raspberry Pi

Advantages

• Simple mechanically
• Easy to automate
• Can point anywhere in the sky
• Very common in professional radio telescopes

Example structure

        Dish

         |

      Elevation pivot

        /   \

       /     \

      |       |

      |       |  Frame

       \     /

        -----

         |

      Azimuth bearing

         |

       Motor

         |

       Pier

Typical components

• Slew bearing / lazy-Susan bearing (~300–400 mm diameter)
• 24 V linear actuator (300–600 mm stroke)
• Worm-gear DC motor for azimuth
• Position encoders

Accuracy of ~0.1–0.3° is easily achievable.

For a 1.5 m dish at 1420 MHz, the beamwidth is roughly 8–9°, so extremely high pointing precision isn’t required.

2️⃣ Equatorial Mount (Tracks sky with one motor)

This is similar to optical telescope mounts.

How it works

• One axis aligned with Earth’s rotation axis
• One motor tracks sidereal rate

Advantages

• Only one motor needed for tracking
• Perfect for long integrations

Disadvantages

• Large dishes require very heavy mounts
• Complex to build
• Usually unnecessary for radio astronomy

3️⃣ Re-purposed Satellite Dish Motor Mount

A very practical low-cost option.

Use a DiSEqC H-H satellite motor designed for 1.2–1.5 m dishes.

Advantages:

• Already designed for dishes
• Computer controllable
• Cheap and robust

But:

• Usually single axis only
• Limited elevation range

Recommended Design for You

For a 150 cm dish used at 1420 MHz:

Motorised Alt-Az Mount

Components:

Azimuth

• 400 mm slew bearing
• 24 V worm gear motor
• Chain or gear drive

Elevation

• 24 V linear actuator (1000–2000 N force)

Control

• Arduino / Raspberry Pi
• Two motor drivers
• Magnetic or optical encoders

Software can convert RA/Dec → Alt/Az automatically.

Example Control Setup

Computer → Arduino → Motor drivers

Software options:

• GNU Radio control script
• Python with PyEphem / Astropy
• Stellarium telescope control

Real Amateur Example

Many amateur hydrogen line telescopes use:

• 1.2–2 m dish
• alt-az mount
• 24 V actuators
• Raspberry Pi control

Tracking accuracy ~0.2°.

Important Mechanical Advice

For a 1.5 m dish:

Weight often 15–30 kg.

Use:

• Solid steel pier
• Wind locking brake
• Limit switches

Wind loading on a dish this size can exceed 200 N in strong wind.

✅ Best overall solution

Alt-Az mount using:

• Slew bearing base
• Linear actuator elevation
• Worm gear azimuth motor