Airspy HF+. SDR Ontvanger
De Airspy HF+ ontvangt van 9kHz tot 31 Mhz en van 60 tot 260 Mhz
Hij werkt samen met computers met de volgende operating systemen:
Linux (bijv. m.b.v. de Raspberry 3)
OSX ( Mac )
The developer of the well known SDR Airspy-R2 has announced a new receiver, developed in cooperation with ITead Studio and a leading semiconductor manufacturer - the Airspy HF+.
The Airspy HF+ operates from 9 kHz to 31 MHz and from 60 to 260 MHz. The new design of the SDR receiver is based on a "Zero-IF" concept, whereby the received signal is mixed directly into the baseband range. This technology avoids many of the problems of classic receiver designs, but also presents developers with new challenges. The Airspy HF+ meets these challenges by using three analog tuners with fixed and tunable band filters. The mixers are designed as harmonic rejection mixers and thus ensure an extraordinarily good linearity and spectral purity of the down-mixed signal. This is important for a good sensitivity, because the cleaner the signal, the less likely it is that a weak signal will be lost in the noise. Two very capable AD-converters are used for digitizing the baseband signal. The subsequent decimation stages (DDC) work with different methods for reducing (decimating) the data rate. The result is a very effective anti-aliasing filter that provides approximately 108 dBc reduction. The resulting signal has a resolution of 18 bits, which is then scaled to 16 bits for transmission via the USB 2 interface.
Such a receiver design requires a very precise AGC to achieve the best possible sensitivity and high dynamic range. The software of the Airspy HF+ microcontroller controls the amplification in each stage of the tuner and the subsequent filters and amplifiers. The result is a dynamic range of theoretically 113 dB, practically 110 dB is achieved (on shortwave). This is an excellent result for such a compact receiver of this price range. The user benefits from the very good linearity and the high dynamic range as the received spectrum is much cleaner and free of artifacts. Manual gain control is not necessary, nor is the use of attenuators, preamplifiers, selective band filters etc.
In addition to the excellent RF characteristics, the developers have achieved an equally remarkable noise reduction at the AF level. Here, the disturbing noise in a desired signal is largely eliminated, without the signal suffering from intelligibility and without too many artifacts in the AF.
Airspy HF+ achieves excellent HF performance by means of a low-loss preselection filter, high linearity LNA, high linearity tunable RF filter, a polyphase harmonic rejection (HR) mixer that rejects up to the 21st harmonic and multi-stage analog and digital IF filtering.
The 6 dB-stepped AGC gain is fully controlled by the software running in the DSP which optimizes the gain distribution in real time for optimal sensitivity and linearity. Harmonic rejection is a key issue in wide band HF receivers because of the large input signal bandwidth of the input signal. The output of the IF-filter is then digitalized by a high dynamic range sigma delta IF ADC for further signal processing in the digital domain.
Excellent FM performance is also achieved by using optimized signal paths composed of band filters, high linearity LNAs with a stepped AGC, a polyphase harmonic rejection mixer and IF filters optimized for the FM broadcast bands.
The amplifier gain is switchable in 3 dB-steps and fully controlled by the AGC running in the DSP. The RF signal is converted to baseband by a high linearity passive mixer with a polyphase harmonic rejection structure. The low-IF signal is then converted into the digital domain by the same IF ADC used in the HF chain.
Extended VHF coverage is assured by a second Band-III tuner up to 260 MHz, but with reduced performance.
The IF analog to digital converter (ADC) is a 4th order multi-bit noise shaping topology; it features very high dynamic range and linearity. The IF-ADC sampling rate is determined by a control algorithm running in the embedded DSP. This advanced technique adjusts the sampling rate depending on the tuning frequency with the goal of avoiding the disturbances and spurs generated by the switching discrete-time sections of the IF-ADC.
Digital Down Converter
Once the IF signal is digitalized, the high sample rate I/Q stream is then frequency translated and processed with cascaded CIC and FIR decimation stages. After every stage, the sample rate is reduced and the resolution increased. The final signal at the output has 18bit resolution and an alias rejection performance of 108 dBc. The data is then scaled to 16bit and sent to the Micro-Controller for streaming over USB.
The main advantages over techniques from the legacy super-heterodynes up to the now mainstream direct sampling is that the whole receiver chain is well protected against out of band blockers while still relaxing the RF filtering constraints, making it simple and cost effective.
The natural filtering of the sigma-delta ADC combined with the excellent linearity and sensitivity of the analog chain reaches an unprecedented level of performance and integration.
Use it over the network!
Connect as many SDR applications as needed to the HF+, over the Internet or in your own local network with near zero latency thanks to the new SPY Server software.
This setup basically brings all the flexibility of Web based SDRs while still benefiting from the full power of desktop applications. The IQ data is processed in the server with state of the art DSP and only the required chunk of spectrum is sent over the network. What is sent is the actual IQ signal, not compressed audio. This means you can use all your favorite plugins to process the IF, eliminate noise and perform heavy lifting of the signals as you are used to do with locally connected SDR’s.
We have a tradition of building multi-tools, so we made sure the SPY Server runs on 32/64bit Windows and Linux on Intel and ARM processors without any compromises. Low cost Raspberry Pi 3 and Odroid boards are in the party.
- HF coverage between 9 kHz .. 31 MHz
- VHF coverage between 60 .. 260 MHz
- -140.0 dBm (0.02 µV / 50 ohms at 15MHz) MDS Typ. at 500Hz bandwidth in HF
- -141.5 dBm MDS Typ. at 500 Hz bandwidth in FM Broadcast Band (60 – 108 MHz)
- -142.5 dBm MDS Typ. at 500 Hz bandwidth in VHF Aviation Band (118 – 136 MHz)
- -140.5 dBm MDS Typ. at 500 Hz bandwidth in VHF Commercial Band (136 – 174 MHz)
- -140.0 dBm MDS Typ. at 500 Hz bandwidth in the upper VHF Band (> 174 MHz)
- +15 dBm IIP3 on HF at maximum gain
- +13 dBm IIP3 on VHF at maximum gain
- 110 dB blocking dynamic range (BDR) in HF
- 95 dB blocking dynamic range (BDR) in VHF
- 150+ dB combined selectivity (hardware + software)
- 120 dB Image Rejection (software)
- Up to 660 kHz alias and image free output for 768 ksps IQ
- 18 bit Embedded Digital Down Converter (DDC)
- 22 bit Resolution at 3 kHz channel using State of the Art DDC (SDR# and SDR-Console)
- +10 dBm Maximum RF input
- 0.5 ppm high precision, low phase noise clock
- 1 PPB frequency adjustment capability
- Very low phase noise PLL (-110 dBc/Hz @ 1kHz separation @ 100 MHz)
- Best Noise reduction of the market using state of the art algorithms
- 2 x High Dynamic Range Sigma Delta ADCs @ up to 36 MSPS
- No Silicon RF switch to introduce IMD in the HF path
- Routable RF inputs with simple modification
- Wide Band RF filter bank
- Tracking RF filters
- Sharp IF filters with 0.1 dB ripple
- Smart AGC with real time optimization of the gain distribution
- All RF inputs are matched to 50 ohms
- 4 x Programmable GPIO’s
- No drivers required! 100% Plug-and-play on Windows Vista, Seven, 8, 8.1 and 10
- Industrial Operating Temperature: -45°C to 85°C
- High Performance Networked HF/VHF Radio
- Ham Radio (HF + 2m)
- Short Wave Listening (SWL)
- AM DX
- FM DX
- VHF-L TV DX
- Remote Telemetry Radio Receiver
- Low Bands IoT
- The HF input port is optimized for the HAM bands higher than 300kHz – A simple modification for VLF is possible by shunting an input capacitor.
- While the in-band performance of the Band-III tuner is excellent, it will require some filtering for very strong out of band signals at multiples of the tuned frequency.
- An RF isolator is required when using long wire antennas with a PC with moderate EMI protection.
Supported Operating Systems
- Windows Vista, 7, 8, 8.1 and 10
- Intel compatible PC
- Raspberry Pi 2 and 3
- Odroid C1, C2 and XU4
- Many other Single Board Computers (SBC)
Minimum hardware requirements
- 1GHz Pentium or ARM
- 1GB of RAM (to run your own OS, HF+ barely needs 1MB of memory)
- High speed USB 2.0 controller