Aurora AU-520M

500W Dual-SCU HF/6m SDR Transceiver with Integrated 8-inch Touchscreen

Experience a new generation of high-power software-defined radio. The FlexRadio AU-520M combines a 500W HF transmitter, dual-SCU receiver system, integrated automatic antenna tuner, mains power supply and Maestro-style controls within a single compact transceiver.

500 Watts. One Integrated System.

The Aurora replaces the traditional collection of a transceiver, external amplifier, automatic tuner and high-current power supply with a single high-efficiency platform. Less cabling, less wasted heat and more room to concentrate on operating.

Serious station performance. Remarkably simple integration.

The FlexRadio Aurora AU-520M is a premium HF/6m software-defined transceiver built for demanding DXers, contesters and operators who want high-power capability without the complexity of a traditional multi-box station. It combines an innovative polar-modulation transmitter with FlexRadio's sophisticated direct-sampling SDR receiver architecture.

Two independent Spectral Capture Units (SCUs) support four slice receivers, true diversity reception and integrated SO2R functionality. The result is exceptional flexibility for monitoring different bands, receiving from separate antenna systems and managing complex station workflows.

The AU-520M also features a built-in 8-inch IPS touchscreen and Maestro-style physical controls, allowing comfortable standalone operation. SmartSDR expands those capabilities further with compatible computer, mobile and remote-control clients.

High-power performance, intelligently delivered

A fundamentally different approach to 500W transmission

Rather than using a traditional linear RF amplifier, Aurora's polar-modulation architecture separates the amplitude and phase components of the transmitted signal. These are processed using efficient switching-mode amplification and sophisticated digital control.

FlexRadio quotes approximately 80% nominal transmitter efficiency, with substantially less power wasted as heat compared with many conventional high-power amplifier arrangements. This enables Aurora to combine considerable RF output with an unusually compact enclosure.

Actual efficiency, consumption and heat output vary with power, mode and operating conditions.

Two independent capture units change what's possible

At the heart of the AU-520M are two independent Spectral Capture Units. Each SCU digitises its own RF input, enabling simultaneous reception from two antenna sources and supporting up to four independently configured slice receivers across the system.

This allows advanced setups that are difficult to achieve with a conventional single-receiver transceiver, including independent band monitoring, diversity reception and sophisticated contest operation.

A receiver designed for demanding band conditions

The AU-520M combines 16-bit direct sampling at 245.76 Msps with sophisticated digital filtering and seventh-order amateur-band preselectors. These filters provide enhanced rejection of unwanted signals, particularly in demanding multi-band and contest environments.

Modern SDR technology. Familiar front-panel operation.

The AU-520M includes an 8-inch high-resolution IPS touchscreen with dedicated tuning controls and physical buttons. The result is a modern, highly capable SDR that still feels like a conventional high-end transceiver when operated directly from the front panel.

The 1920 × 1200 screen supports two panadapter and waterfall views on the integrated display. A compatible external monitor can also be connected using the available HDMI output.

Your radio, wherever you want to operate

SmartSDR delivers flexible control of the AU-520M's four slice receivers, operating modes, audio routing and spectrum displays. In addition to the built-in front panel, compatible SmartSDR clients allow operation through a computer, supported mobile devices or an external Maestro controller.

SmartLink supports remote operation over a suitable internet connection, while MultiFlex allows two compatible SmartSDR clients to access the same radio. Digital Audio eXchange (DAX) provides audio and IQ data channels for compatible applications.

Individual clients may require separate software or licences. Feature availability depends on the installed SmartSDR version.

Built for complex, high-performance stations

The AU-520M supports two high-power transmitting antenna connections, two dedicated receive-only antenna inputs and two transverter/exciter ports. Together with its dual-SCU receiver system, these interfaces allow flexible station configurations without relying on multiple separate receivers.

Integrated GNSS frequency stabilisation

The Aurora AU-520M includes a multi-system GNSS receiver supporting GPS, Galileo, GLONASS, QZSS and SBAS. With appropriate satellite reception, this helps maintain highly accurate frequency operation without routine manual oscillator adjustment.

FlexRadio specifies frequency stability of approximately 0.001ppm with GNSS and 0.5ppm from the internal TCXO. An optional high-performance GPSDO can also provide a highly stable 10MHz output reference for suitable external equipment.

AU-520M vs AU-510M: which is right for you?

Both the AU-510M and AU-520M provide the same 500W HF/200W 6m output, integrated high-power antenna tuner, AC power supply, SmartSDR ecosystem and 8-inch Maestro-style touchscreen. The distinction is in the receiver architecture and advanced station capabilities.

Advanced digital operation and clean transmit audio

The AU-520M supports conventional SSB, CW, AM and FM, together with compatible RTTY and software-based digital modes. SmartSDR's DAX interfaces provide digital audio and IQ routing for supported computer applications.

SmartSignal adaptive predistortion is designed to improve transmitter linearity, while Controlled Envelope SSB (CESSB) can improve the effective speech power under suitable conditions.

High-power operation without a separate PSU

The Aurora's built-in AC power supply operates across an 80–264V AC input range, making it suitable for UK mains operation and compatible international supplies. There is no need for a separate high-current 13.8V DC power supply.

FlexRadio quotes approximately 35W power consumption in receive mode and 675W in transmit mode under its specified operating conditions.

Equally at home in the shack, contest station or DXpedition

Important information before ordering

Transmit power: Up to 500W PEP on supported HF amateur bands and 200W PEP on 50MHz. Antennas, coaxial cables, switches and accessories must be appropriately rated.

Power supply: Integrated 80–264V AC input. Direct 13.8V DC operation is not supported.

Antenna tuner: The internal ATU matches suitable antenna systems within a specified 3:1 SWR range. Any external ATU must be rated for the intended operating power.

GNSS/GPSDO: Integrated GNSS frequency reference is standard. The high-performance GPSDO is optional.

Software: Some features and client capabilities depend on the installed SmartSDR firmware, relevant licences and future software releases.

Aurora User Guide

View the official Aurora user guide for detailed operating instructions, system connections, technical guidance and setup information.