Aurora AU-520 Dual-SCU 500W Integrated SDR Transceiver

The AU-520 raises the bar for serious HF and 6m operators, integrating a full-featured software-defined transceiver, high-efficiency 500W amplifier, automatic antenna tuner, and wide-range AC power supply—all in one compact, rugged chassis.

Built around the same cutting-edge RF architecture as its siblings, the AU-520 delivers up to 500W PEP with industry-leading efficiency—up to 80% peak—reducing heat and power demands while minimizing size and complexity in your station setup.

Designed without a built-in display or Maestro front panel, the AU-520 is ideal for remote stations, rack-mounted installations, or operators who prefer external control via SmartSDR™ for Windows, macOS, iPad®, iPhone®, or Maestro™ clients. Radios are licensed for SmartSDR Basic.

The AU-520 features two independent SCUs (Spectral Capture Units), each capable of digitizing wide portions of the HF/6m spectrum simultaneously. This dual-SCU configuration allows for up to 4 slice receivers and 4 independent panadapters, making it a powerful choice for contesting, diversity reception, multi-band monitoring, and advanced digital operation – all while maintaining full coverage from 30 kHz to 54 MHz.

Inside the AU-520:

• 500W high-efficiency transmitter

• Integrated wide-range AC power supply

• Automatic antenna tuner

• SmartSignal™ adaptive predistortion for outstanding spectral purity

• Controlled Envelope SSB (CESSB): Up to 3 dB more talk power without distortion

• MultiFlex™: Enables two SmartSDR clients to operate independently on the same radio

With its dual-SCU design and fully integrated architecture, the AU-520 delivers the flexibility and performance of a multi-component station—without the clutter. Whether you’re operating from across the shack or across the globe, the AU-520 is built to handle high-demand operation with ease.

The AU-520 is a true SO2R (Single Operator Two Radio) solution, designed for serious contesting with dual SCUs, integrated 7th-order bandpass filters, and full isolation between receivers. Built-in OTRSP support makes integration with logging software like N1MM+ effortless—no extra hardware or wiring needed. It’s a plug-and-play SO2R contest powerhouse, ready right out of the box.

Full Specifications of the FlexRadio AU-520

General

• Remote Operation: SmartLink™ included

• Delivered with the current licensed SmartSDR Basic firmware

• Client Options: PC, Mac, iPhone®, iPad®, Maestro™

• Integrated GNSS Receiver: 12-channel GPS, Galileo, GLONASS, QZSS, SBAS

• Time to First Fix (Cold): <35s

• Frequency Stability (0°C–50°C): 0.001 ppm (GNSS), 0.5 ppm (TCXO)

• Optional High-Performance GPSDO: 10 MHz output, 5 × 10⁻¹³ stability over 24 hours

• External 10 MHz Reference Input: Yes

AU-520 Receiver

• Spectral Capture Units (SCUs): 2

• Independent Band/Mode Receivers: 4

• Slice Receivers: 4

• Frequency Coverage: 30 kHz–54 MHz

• 2 kHz RMDR: 110/115 dB

• Dynamic Range (Max Zoom): >145 dB

• ADC: 16-bit @ 245.76 Msps direct sampling

• Amateur Band Preselectors: 7th order

• DAX / DAX IQ Channels: 4 / 4

• Receive-Only Ports (Base / Including XVTR Ports): 2 / 4

• Full Duplex RX/TX Operation: Yes

Aurora Transmitter

• 160m–10m Transmitter Output (Amateur Bands Only): 1–500W PEP (125W AM)

• 6m Transmitter Output: 1–200W PEP (50W AM)

• Harmonic Suppression: ≤ –60 dBc

• Transverter Ports: 2

• Transverter IF Frequency Coverage / Power: 100 kHz–54 MHz / adjustable up to +10 dBm

• Integrated Automatic Antenna Tuner Range: 3:1 SWR

• Adaptive Pre-distortion: Included (SmartSignal™)

• Supported Modes: SSB, CW, AM, FM, RTTY, Digital

Spectrum/Waterfall Display

• Spectrum/Waterfall Displays (Max): 4

• Spectrum/Waterfall Bandwidth (Min / Max): 5 kHz – 14 MHz

• Spectrum Resolution Bandwidth (Min): 1.46 Hz/pixel (bin)

• Spectrum Dynamic Range (Max Zoom In): >145 dB

• External Display Support: HDMI®