Airspy HF+ Discovery - High-Performance SDR Receiver

Airspy HF+ Discovery

The Airspy HF+ Discovery sets a new standard in reception performance, equipped with extra presets for all supported bands. It also features a new DSP core that optimizes the distribution of acquired data and real-time filtering parameters, effectively reducing noise.

The signal structure includes data converters with an extremely high dynamic range, along with highly efficient passive mixers with superb multi-stage harmonic rejection. It includes presets for band-scanning that eliminate unwanted interference while preserving the receiver's dynamic range. With its extremely powerful signal processing capabilities and incredibly low noise level, the HF+ Discovery is an ideal companion for any reception that demands high performance.

Both the architecture and the level of integration achieved in this design allow us to deliver outstanding reception at a very affordable price. It supports all major SDR software. Check out the download page.

Are you ready to discover all the signals hidden in your spectrum?

Enhanced Architecture

Unmatched Noise Reduction Processing

We have spent significant time trying to understand RF noise, its structure, and how it interacts with legitimate signals. Today, we offer one of the most flexible and acoustically pleasant noise reduction algorithms on the market. The scope ranges from eliminating hiss while providing quality sound reproduction of FM broadcast signals to amplifying weak SSB signals with low noise levels. Our algorithm does not cut highs to falsely increase the impression of loudness and avoids typical high-frequency artifacts that are a problem with popular noise reduction algorithms such as LMS and spectral subtraction.

Here is a very weak SSB signal in the 40m band, with or without our digital noise reduction. Try it out yourself!

https://airspy.com/downloads/dnr_ssb.mp3

Another recording in the 80m band during layering:

https://airspy.com/downloads/Csete_80m_20171118_231457Z_3765000Hz_AF.mp3

Unprocessed audio signal:

Audio signal processed with our digital noise reduction:

State-of-the-Art Streaming Technology with Art SDR!

We have concentrated cutting-edge DSP and networking technologies into our SpyServer software to allow multiple users to stream very high-quality IQ data from the same receiver simultaneously. We made no compromises on quality, as is typically the case in web SDR interfaces. You will receive genuine IQ data that you can process with your plugins and extract all information from it. The server software is highly extensible and can run on computers as small as the Orange Pi Zero and also on high-end 64-bit servers with multiple cores/CPUs, including the popular Raspberry Pi series.

New Interference Architecture

HF Tuner

The Airspy HF+ Discovery achieves excellent HF performance using a low-loss preselection filter, high-linearity LNA, a highly linear tuneable RF filter, and a multi-stage harmonic rejection mixer (HR) that rejects up to 21 harmonics, combined with multi-stage analog and digital IF filtering. The 6dB gain AGC reception is fully controlled by software running in DSP, optimizing the reception distribution in real time for optimal sensitivity and linearity. Harmonic rejection is a crucial issue in broadband HF receivers due to the large bandwidth of the input signal. The output of the IF filter is then digitized by a high-dynamic-range Sigma Delta IF ADC for further signal processing in the digital domain.

VHF Tuners

Excellent FM performance can also be achieved using optimized signal paths composed of bandpass filters, high-linear LNA with step AGC, multi-stage harmonic rejection mixers, and IF filters optimized for FM broadcast bands.

The gain of the receiver is switchable in 3 dB steps and is fully controlled by AGC running in DSP. The RF signal is converted to baseband using a high-linearity passive mixer with a multi-stage harmonic rejection structure. The low IF signal is then converted into the digital domain using the same IF ADC employed in the HF chain. Extended VHF coverage up to 260 MHz ensures a second Band-III tuner, but in this case, performance may be slightly reduced.

IF Sampling

The analog-to-digital signal IF converter (ADC) utilizes a 4th-order noise shaping multi-bit topology; it features very high dynamic range and linearity. The sampling frequency of the IF-ADC is determined by a control algorithm running in the embedded DSP. This advanced technology adjusts the sampling frequency depending on the tuning frequency to avoid disturbances and spikes caused by switching discrete time portions of the IF-ADC.

Digital Downconverter

Once the IF signal is digitized, the frequency of the high-sampling-rate I/Q stream undergoes a folding and is processed through cascaded decimation phases of CIC and FIR. After each phase, the sampling frequency is reduced, and the resolution is increased. The final output signal has a resolution of 18 bits and an alias rejection performance of 108 dB. The data is then adjusted to 16 bits and sent to the microcontroller for streaming via USB.

Architectural Advantages

The main advantages over older technologies from super-heterodyne to today’s direct sampling lie in the fact that the entire receiving chain is well shielded from band blockers while still relaxing the RF filtering constraints, making it straightforward and cost-effective. Natural sigma-delta ADC filtering, combined with excellent linearity and sensitivity of the analog chain, brings unprecedented levels of performance and integration.

Use it on the Network!

With the new SPY Server software, you can connect as many SDR applications as you need to the HF+ Discovery over the internet or through your local network, with nearly zero latency.

This setup essentially brings all the flexibility of web SDR while leveraging the full power of desktop applications. IQ data is processed on the server with high-end DSP, and only the requested portion of the spectrum is sent over the network. A true IQ signal is sent, not compressed audio. This means you can use all your favorite plugins for IF processing, eliminating noise and performing heavy signal lifting as you are accustomed to with locally connected SDR. Our tradition is to create multifunctional tools, so we ensured that the SPY Server runs on 32/64-bit Windows and Linux, on both Intel and ARM processors with no compromises. It is also compatible with low-cost boards like Raspberry Pi 3 and Odroid.

Technical Specifications

• HF coverage from 0.5 kHz to 31 MHz
• VHF coverage from 60 to 260 MHz
• -140.0 dBm (0.02 µV / 50 ohms at 15 MHz) MDS Typ. at 500 Hz bandwidth in HF
• -141.5 dBm MDS Typ. at 500 Hz bandwidth in FM broadcast band (64–118 MHz)
• -141.0 dBm MDS Typ. at 500 Hz bandwidth in VHF flight band (118–260 MHz)
• +15 dBm IIP3 at HF at maximum gain
• +13 dBm IIP3 at VHF at maximum gain
  • 110 dB dynamic range of blocking (BDR) in HF
• 95 dB dynamic range of blocking (BDR) in VHF
• 150+ dB combined selectivity (hardware + software)
• 120 dB image rejection (software)
• Multi-stage tracking filters to suppress close-range interference
• New very powerful presets for HF with 4 filters (edges at ~DC, 5, 10, 17 and 31 MHz)
• New very powerful presets for VHF (airband, HAM, commercial, and military VHF)
• New very powerful presets for FM bands (Japan, USA, EU, OIRT)
• Aliasing up to 660 kHz and output without image for 768 ksps IQ
• 18-bit built-in digital downconverter (DDC)
• 22-bit resolution at 3kHz channel using top DDC (SDR# and SDR-console)
• +10 dBm maximum RF input
• 0.5 ppm very accurate clock with low phase noise
• 1 PPB frequency setting capability
• Very low phase noise PLL (-110 dBc/Hz @ 1 kHz offset @ 100 MHz)
• The best noise reduction on the market using top-notch algorithms
• 2 x high dynamic range Sigma Delta ADCs at up to 36 MSPS
• One RF input to cover all bands with high linearity switching
• Improved input matching nearly down to DC
• Intelligent AGC optimizing real-time reception distribution for best SNR under all circumstances
• Requires no drivers! 100% ready to use on Windows Vista, Seven, 8, 8.1, and 10
• Industrial operating temperature: -45 °C to 85 °C

• High-performance network HF/VHF radio
• Ham radio (HF + 2 m)
• Shortwave listening (SWL)
• AM DX
• FM DX
• VHF-L TV DX
• Remote telemetry radio receiver
• Low-band IoT

Supported Software

• Gold standard SDR#
• Another excellent SDR suite, SDR-Console
• Swiss army knife SDR for Linux and Mac, GQRX
• Network server for use with SdrDx for Mac, AirspyHF+ Mac ServerGQRX
• All ExtIO based software (HDSDR, Studio1, etc.) via ExtIO by Hayati Ayguen
• All ExtIO based software (HDSDR, Studio1, etc.) via ExtIO by Andrea Montefusco
• Check out the complete list of tools on our download page

Supported Operating Systems

• Windows Vista, 7, 8, 8.1, and 10
• Linux
• *BSD
• OSX

Supported Hardware

• PC compatible with Intel
• Raspberry Pi 2 and 3
• Odroid C1, C2, and XU4
• Many other single-board computers (SBC)

Minimum Hardware Requirements

• 1 GHz Pentium or ARM
• 1 GB RAM (your OS needs barely 1 MB of memory for HF+ to function)
• High-speed USB 2.0 driver

Fully Open-Source Driver

• Open-source driver and cross-platform user mode libairspyhf on github

Firmware Updates

• R2.0.0 2019-05-02 (Changelog)