MOX_RV3 Antenna 868 MHz 

Professional directional antenna for long-range RC systems

The Moxon antenna in PCB design is a proven solution for ExpressLRS, TBS Crossfire and other 868 MHz protocols. Precise manufacturing on 1.6mm FR4 laminate with factory-mounted RG402 cable of ~12 cm length ensures repeatable parameters and simple installation.

History and operating principle

The Moxon antenna was developed by Les Moxon (G6XN) in 1993 as a compact alternative to the Yagi antenna. The design derives from a rectangular "folded dipole" antenna and features a unique shape resembling a rectangle with bent corners. The main advantage is achieving directionality with dimensions 30% smaller than a classic Yagi with similar parameters.

The key to Moxon's operation is the precisely calculated distance between the active element and reflector - capacitive coupling is created at the ends, which provides excellent front-to-back ratio while maintaining broad characteristics in the side planes.

Real-World Engineered, Not Just Calculated

This antenna is the result of extensive R&D with multiple prototype iterations and real-world testing. Unlike many antennas on the market that exist only as theoretical calculations or untested simulations, our Moxon has been refined through:

• 7+ prototype versions tested in actual flight conditions
• Field validation with ELRS and Crossfire systems
• Range testing at various power levels and environments
• SWR and impedance optimization

Theory meets reality - because what works in simulation doesn't always perform in the field. Every dimension and detail has been validated through actual use, not just software predictions.

Technical specifications

Electrical parameters:

• Center frequency: perfectly 868 MHz 
• Operating band: 840-920 MHz (SWR < 1.5)
• Impedance: 50 Ω
• SWR at band center: < 1.1
• Return Loss: > 17 dB
• Gain: 5.5 dBi (main direction)
• Front-to-back ratio: > 12 dB

Radiation pattern:

The Moxon antenna exhibits an interesting property - very wide coverage in the plane perpendicular to directionality:

This wide pattern (>200° in one plane) makes the Moxon excellent for maneuvering drones while maintaining directional gain and rear signal suppression.

Mechanical parameters:

• Material: FR4 laminate 1.6 mm
• Copper thickness: 35 μm
• Cable: RG402 semi-rigid, length about 12 cm
• Connector: SMA male (RP-SMA available)
• Dimensions: 98 x 42 mm
• Weight: 55g with cable

Why 12 cm cable?

This length minimizes interactions between the antenna and transmitting device - the antenna's near field doesn't reach the transmitter electronics. Result: stable parameters regardless of enclosure type or mounting, no impedance detuning and maximum power transfer.

PCB construction advantages

Production repeatability

PCB technology ensures dimensional tolerance. Every manufactured antenna has identical parameters - no "lottery" effect known from hand-made antennas. Particularly important for Moxon geometry, where precise spacing between elements is critical.

But we don't stop there! Each single antenna undergoes individual testing and fine-tuning on a professional vector network analyzer. We verify and additionally adjust every piece to achieve perfect resonance at 868 MHz. The customer receives not just a good antenna, not just an adequate antenna, but a perfectly tuned antenna. This individual attention to each product guarantees that you receive equipment with parameters matching or exceeding specifications.

Losses and bandwidth

Bandwidth >80 MHz results partially from small losses in FR4 laminate, which "flatten" the SWR characteristic. Disadvantage or advantage? In practice - advantage: antenna remains well matched over a wide range of temperatures and humidity, tolerates proximity to obstacles.

Mechanical stability

Our proprietary cable mounting solution ensures exceptional durability of the critical connection point. The RG402 cable is attached using a reinforced soldering technique with additional mechanical strain relief, making the antenna truly robust. The rigid PCB structure doesn't change geometry under wind or vibrations - no bent elements, no detuning. This combination of solid PCB construction and reinforced cable attachment creates an antenna that maintains stable parameters over years of use, even in demanding field conditions.

Practical applications

ExpressLRS / Crossfire

Ideal choice for ground stations and transmitter modules. 5.5 dBi gain means approximately 3.5x stronger signal in flight direction compared to omnidirectional antenna. In practice, this translates to 60-80% range increase at the same power.

Diversity systems

Excellent as directional antenna in diversity setup with omnidirectional antenna. Wide pattern (>200°) ensures smooth switching between antennas without dead zones.

Meshtastic

For point-to-point links between nodes. Directionality allows creating stable long-distance connections while maintaining low power consumption.

Tracking

Mounting on tracking system utilizes full antenna potential. Wide pattern makes it easier to "catch" the drone after takeoff.

LORAWAN
It works perfectly in LoRaWAN applications for Smart City, industrial monitoring, telemetry systems and building automation. The directional radiation pattern allows for increased link range while reducing interference from side directions.

Comparison with other antenna types

Installation tips

1. Orientation: For typical FPV applications mount vertically (matching drone antenna polarization)
2. Height: Every meter of mounting height can add kilometers of range
3. Direction: Front part of antenna (side without reflector) towards flight direction
4. Clearance: Minimum 30 cm from large metal surfaces

RG402 cable technical data

• Impedance: 50 Ω
• Loss at 868 MHz: ~0.3 dB/m (at 12 cm: only 0.036 dB !)
• Outer diameter: 4.5 mm
• Minimum bend radius: 5 mm

Package contents

• Moxon PCB antenna with soldered RG402 cable
• SWR measurement - label

Warranty and certificates

24 months manufacturer warranty. Each antenna tested on vector analyzer. 

Fun fact: Les Moxon originally designed his antenna for HF (shortwave) bands, where 30% size reduction meant the difference between a 20-meter and 14-meter antenna. Today his design finds applications from MHz to GHz - from marine communications to WiFi and drones.

This antenna can be used with any system that works on 868,900,915Mhz  band - frsky, TBS, Radiomaster, iflight, wifi routers, expresslrs, betafpv, Orqa etc. and have connector or can be modded to use external antenna.

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