Moon RF: Open-Source 240-Antenna Phased Array for Bouncing Signals Off the Moon
A DIY Moon Bounce System You Can Build at Home
Moon RF, formerly known as open.space, is an open-source initiative that aims to democratize Earth-Moon-Earth (EME) communication — the practice of bouncing radio signals off the Moon's surface to enable long-distance communication. The project provides both hardware and software for building phased array antenna systems at a fraction of traditional costs.
The Technology
Moon RF uses software-defined radio (SDR) technology combined with digital phased array design. The core building block is the QuadRF tile, a 4-antenna SDR module:
- Frequency range: 4.9-6.0 GHz (C-band), full duplex operation
- Per-antenna bandwidth: 40 MHz with 8+8-bit I/Q resolution
- Transmit power: 1W per antenna with ~1.2 dB receive noise figure
- FPGA: Lattice ECP5 with sub-1ms latency for beamforming
- Price per tile: $49-99 (estimated)
Product Tiers
The project offers three scalable configurations:
1. QuadRF Tile ($49-99): Standalone 4-antenna SDR module. Useful as a general-purpose MIMO radio, for direction finding, RF exploration, or as a building block for larger arrays.
2. Mini Array ($899-1,499): 18 tiles (72 antennas) with ~60-degree beam steering. Applications include drone HD links, mobile field operations, and receiving satellite downlinks. Peak power: 450W.
3. Moon Array ($2,499-4,999): 60 tiles (240 antennas) designed specifically for Earth-Moon-Earth experiments and radio astronomy. Expected to ship with ~34 dBi array gain and ~52.6 dBW EIRP. Expected shipping: July 2026.
Why This Matters
EME communication has traditionally been the domain of well-funded institutions and serious amateur radio operators with massive dish antennas. Moon RF's phased array approach offers several advantages:
- No mechanical pointing: Electronic beam steering replaces manual antenna tracking
- Scalability: Start small, add tiles as budget allows
- Open source: Both hardware designs and software are fully open
- Multi-use: The same hardware works for drone links, satellite reception, and RF exploration
- Low cost: A full moon-bounce array for under $5,000 is unprecedented
Applications Beyond Moon Bounce
The phased array technology has practical applications closer to Earth:
- Backhaul communications: High-gain directional links for rural connectivity
- Drone operations: Long-range telemetry and HD video links
- Direction finding: Fox hunting, geolocation, and spectrum monitoring
- 5G base stations: Open-source cellular infrastructure
- Radio astronomy: Citizen science observations
Availability
Hardware is expected to begin shipping in July 2026. An amateur radio license (Technician+ in the US) is required for operation.