How to Machine Radio and Satellite Dish Parts with a Desktop CNC

Radio astronomy projects often require specialized hardware that is difficult or expensive to purchase commercially. From satellite tracking systems to Earth–Moon–Earth (EME) communication experiments, hobbyists frequently need custom components.

Desktop CNC machines now make it possible to machine these parts directly in a small workshop. In this project, a desktop CNC was used to manufacture several components for the Sandland Radio Observatory in Wisconsin, including a microstrip filter, a satellite dish elevation indicator, and custom observatory signage.

The manufacturing work described here was carried out for the Sandland Radio Observatory, a privately operated experimental facility located in Wisconsin.

At the center of the observatory stands an 18-foot geodesic radar dome that houses a satellite communication system. The current setup includes a 6-foot satellite dish used for radio astronomy observations and satellite tracking. Plans are underway to upgrade to a larger antenna to support more advanced experiments.

The observatory is used for several types of radio research and communication activities, including:

• Amateur satellite tracking

• High-frequency communication experiments

• Ham TV signals from the International Space Station

• Earth–Moon–Earth (EME) “moon bounce” communication

Many of these projects require custom hardware that cannot easily be purchased off-the-shelf. Components such as specialized RF filters, antenna mounts, and calibration tools often need to be fabricated specifically for a given experiment.

This need for customization made desktop CNC manufacturing a practical solution.

The manufacturing in this project was performed using a Carvera Air desktop CNC machine. Unlike traditional industrial CNC systems, desktop models are compact, enclosed, and designed for small workshops or maker spaces.

Despite their smaller footprint, modern desktop CNC machines are capable of performing several types of precision manufacturing.

One of the most useful capabilities for electronics enthusiasts is subtractive PCB fabrication. Instead of printing circuits with chemicals, the CNC machine engraves copper traces directly into copper-clad boards.

This method allows rapid prototyping of RF circuits, filters, and signal processing boards without relying on external PCB fabrication services.

Many radio components require rigid metal parts for structural support or shielding. Desktop CNC machines can cut aluminum and other soft metals to produce brackets, housings, and mechanical mounts.

These components are often required for antenna positioning systems and satellite tracking equipment.

Laser engraving allows precise markings to be added to metal or wood surfaces. For instrumentation, this capability can be used to create measurement scales, labels, or calibration markings.

Some desktop CNC machines also support rotary tools and other accessories, allowing them to handle cylindrical objects or more complex three-dimensional machining tasks.

For hobbyists working on diverse projects, having multiple manufacturing methods in a single machine can greatly simplify the workflow.

One of the primary goals of the project was to produce a custom microstrip hairpin filter tuned to 1296 MHz. Filters like this are commonly used in microwave communication systems to isolate specific frequencies and remove unwanted signals.

Commercial RF filters can be expensive and often have long delivery times, so the idea was to manufacture a custom version using the desktop CNC machine.

The design workflow involved several steps:

1. Initial circuit designs were generated using online RF design tools.

2. The layouts were refined using graphics software such as GIMP and Inkscape.

3. The resulting vector paths were exported as SVG files.

4. These files were then converted into CNC toolpaths for engraving.

The final circuit pattern was etched into a copper-clad board using the CNC machine.

SMA connectors salvaged from a failed wideband low-noise amplifier were desoldered and reused for the filter assembly.

Once completed, the filter was tested using a NanoVNA vector network analyzer to evaluate its performance at the target frequency.

The filter did not perform as expected during testing. The NanoVNA analysis showed no clear signal attenuation at the target frequency, indicating that the filter was not functioning correctly.

Several possible factors may have contributed to this outcome:

• Errors in the original circuit design

• Grounding issues due to the single-layer board construction

• Manufacturing tolerances affecting the RF geometry

Although the component did not function as intended, the experiment provided valuable insight into the challenges of precision RF manufacturing.

Another component produced during the project was a custom elevation indicator for the satellite dish.

Satellite tracking systems typically rely on computer-controlled motors to position the antenna. However, a physical reference indicator can be extremely useful for quickly verifying the dish angle during manual adjustments or troubleshooting.

The indicator was created using laser engraving on an aluminum plate. Degree markings were engraved along the arc of the plate to provide a clear visual scale.

The engraved plate was mounted on a simple backing made from scrap wood, forming a durable mechanical indicator.

During the first attempt, the engraving process was interrupted when the laser head collided with a mounting bracket. This caused a shift in the engraving path and resulted in a discontinuity in the markings.

After adjusting the setup and repeating the process, the second attempt was successful.

The completed indicator was installed on the pan-tilt mount of the satellite dish, where it now provides a quick visual reference for dish elevation during operations.

The final project component was a wooden sign for the observatory itself.

This task served as a practical test of the machine's traditional carving capabilities.

The sign was carved from a wooden board and featured the name of the observatory along with decorative text.

The carving process used standard CNC milling tools rather than the laser module.

During the carving process, the machine occasionally behaved unexpectedly, briefly skipping sections of the toolpath before returning to complete them later.

Despite these minor irregularities, the machine successfully finished the carving.

The completed wooden sign was installed on the exterior of the observatory’s geodesic dome, adding a personalized touch to the facility.

This project demonstrated that desktop CNC machines can play an important role in experimental radio projects.

Several key lessons emerged during the process:

Desktop CNC machines allow hobbyists to experiment with custom hardware without waiting for external manufacturing services.

The ability to switch between PCB engraving, metal machining, and wood carving makes a single machine useful for a wide variety of tasks.

RF components such as filters require extremely precise dimensions. Even small variations in trace width or grounding structure can significantly affect performance.

Successful designs often require multiple iterations and testing cycles. Desktop manufacturing tools make this iterative process more accessible.

As desktop manufacturing technology continues to evolve, its role in amateur radio and experimental electronics is likely to expand.

Potential future applications include:

• Custom antenna mounts and tracking systems

• Helical antenna fabrication using rotary machining

• RF shielding enclosures

• Prototype microwave circuits

• Experimental satellite communication hardware

For hobbyists and independent researchers, having the ability to fabricate components on demand opens new opportunities for innovation.

Desktop CNC machines are becoming valuable tools for makers working on radio and satellite projects. From machining RF components to engraving measurement tools, CNC manufacturing enables faster prototyping and greater customization for amateur radio and experimental communication systems.