Category: Airspy

Airspy HF+ Released!

The much anticipated Airspy HF+ has just been released for sale. The cost is $199 USD plus shipping from the manufacturer iTead in China which costs about $6 for a registered air mail parcel or $19 for DHL express delivery to the USA. There was a coupon available via this tweet, but it ran out within hours.

The HF+ is also available for preorder for US/Canada customers over at the airspy.us reseller. Currently there is a last chance $50 coupon available for US/Canada residents purchasing from airspy.us by using the code provided in the link. We don't know how long that coupon will last though.

Note that we believe that these are preorders, with shipping expected to commence in early December.

If you didn't know already the Airspy HF+ is a HF/VHF RX only SDR which has extremely high dynamic range and excellent sensitivity. The high dynamic range means that the SDR is unlikely to ever overload on strong signals meaning that no external filtering which can reduce SNR/sensitivity is required. The minimum discernible signal (MDS) measurements are also excellent meaning that sensitivity to weak signals is excellent too. With high dynamic range, great sensitivity and low cost combined, this SDR blows most of the current offerings out of the water by being able to 'just work' without the need to fiddle around with gain sliders, filters or attenuation.

Airspy HF+: Why Linearity Matters
Airspy HF+: Why Linearity Matters

The only disadvantage to similar offerings like the Airspy R2/Mini or SDRplay is the reduced frequency range and bandwidth specs. On the HF+ the frequency range tops out at 260 MHz and the bandwidth at 680 kHz. The Airspy R2/mini/SDRplay units have frequency ranges that go up to 1.8 - 2 GHz, and have bandwidths of up to 10 MHz. But this is an SDR designed for DXing or pulling in those weak signals, so wideband operation is not a major concern for that application.

We have a review of a prototype version of the Airspy HF+ that we received earlier in the year available here. It's one of the most impressive low cost SDRs that we've seen to date. (We consider sub $300 USD as low cost, and $20 RTL-SDRs as ultra-low cost). You can also freely test some publicly available Airspy HF+ units that were provided to reviewers and developers over the internet.

Technical specifications

  • 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
  • Full details at https://airspy.com/airspy-hf-plus/
The Airspy HF+
The Airspy HF+

Testing Public Airspy HF+ SpyServers over the Internet

SpyServer is a streaming server for SDR# which allows you to use Airspy and RTL-SDR radios remotely over a network connection. There is now a list of publicly available SpyServers that you can connect to over on the airspy.com website.

The servers that are currently online include some streaming from Airspy HF+ devices, which is the hotly anticipated but as of yet unreleased HF receiver from Airspy. Over the last few months and weeks a number of prototype devices went out to testers and programmers and some have now put them online with a SpyServer. There are also some Airspy One/Mini and RTL-SDR devices available for streaming too.

To connect to one of the servers simply download the latest version of SDR# from airspy.com, and then in SDR# select SpyServer from the Source menu. Enter the URL from the list into the box and press the play button up the top. Note that you must ensure that there are no spaces after entering the URL in SDR#.

Most servers are locked to a particular frequency band, but some allow for free tuning. But if more than one person is connected to the server free tuning will be locked until there is only one person connected again. Currently streaming from most servers seems smooth, but it's possible that some may struggle if many users are connected at once.

If you want to set up your own SpyServer then we recently put up a tutorial which is available here.

The current list of SpyServers
The current list of SpyServers

Alternative streaming SDR lists for other non-Airspy SDR hardware include sdr.hu and websdr.org, but those stream compressed audio instead of IQ data.

RTL-SDR Tutorial: Setting up and using the SpyServer Remote Streaming Server with an RTL-SDR

A number of people have asked how to use SDR#'s SpyServer with an RTL-SDR. In this tutorial we will show how to set up SpyServer on both Windows and Linux systems. We try to assume as little knowledge as possible, but we do assume that you have decent experience with computers. Also for the Linux/Raspberry Pi setup we need to assume that you have some basic experience with Linux and setting up Raspberry Pi's.

What is SpyServer?

SpyServer is a free RTL-SDR compatible SDR server that is designed to work with the popular SDR# software. It is actually designed for the Airspy range of products, but the author has also made it compatible with RTL-SDR dongles. Running a SpyServer allows you to connect to and use a remotely positioned RTL-SDR over a network connection (such as a local LAN/WiFi or the Internet). Once connected, using the dongle is the same as if the dongle was directly connected to the users PC.

An example SpyServer Overview
An example SpyServer Overview (Can use an RTL-SDR instead of the Airspy HF+)

Remote servers are useful as you may want to set up an antenna in a remote location (such as up on your roof or shack), and don't want to run a long lossy coax cable down to the PC. Instead you could run Ethernet cable, or avoid cables by using WiFi. All you'd need is power for a remote computing device like a Raspberry Pi 3. Perhaps you also have a great antenna location at a friends house, or other property and want to access that antenna remotely. Or maybe you want to use your radio while travelling.

SpyServer is similar to another tool that you may already be familiar with called rtl_tcp. However, SpyServer is regarded as superior because it is signficantly more efficient at network usage. Instead of sending the entire raw data like rtl_tcp does, SpyServer only sends the IQ data of the currently tuned in signal. Waterfall data is processed on the server and sent in compressed form. There is one disadvantage to SpyServer in that it requires slightly more powerful computing hardware like a Pi 2 or Pi 3, whereas rtl_tcp can run on the lowest end hardware.

Network usage when streaming with SpyServer will be about 120 KB/s when listening to WFM and about 38 KB/s when listening to narrow band modes for one client being connected. Multiple clients can connect to the SpyServer and share the same currently tuned bandwidth.

Continue reading →

SpyServer Updated: Very Efficient Network Usage with 8-Bit PCM Mode

Over the last month SDRSharp's SpyServer has been updated several times. SpyServer is a streaming server for SDR# which allows you to use Airspy and RTL-SDR radios remotely over a network connection.

The updates brought improvements such as IQ PCM compression at various bit depths including an efficient 8-bit mode, removing the DC spike residual in the 8-bit streaming mode, and recently improving the 8-bit mode to work like lossy compression for strong signals. 

We tested the new 8-bit PCM streaming mode and found it to be extremely efficient with network usage. When streaming at 2 MHz with an RTL-SDR a WFM signal on the older SpyServer versions used to use about 1.2 MB/s without any compression modes, and now with 8-bit compression active it only uses 322 KB/s. A NFM signal used to require 120 KB/s, now only requiring about 38 KB/s. No DC spike is present and no degradation in reception quality is noticeable unless the signal requires over 70 dB of dynamic range, which is unlikely for most signals.

If you've had trouble with SpyServer or rtl_tcp not working well on your slow network connection, then the new updated SpyServer may be the solution for you.

Prog, the author of SDR# and SpySever writes about the update on the Airspy group:

This new development allows you to stream large signals over 8bit and reduce the network bandwidth.

The server will try to pack the useful signals into whatever bit depth you select ensuring optimal SNR for the transport. No manual scaling required.

SpyServer with 8-Bit PCM IQ Compression
SpyServer with 8-Bit PCM IQ Compression

Airspy HF+ Real World Performance Examples by the Author of GQRX up on YouTube & Twitter

Alexander Csete (OZ9AEC) is the programmer behind the popular GQRX software. Recently Alexander has received a review sample of the upcoming Airspy HF+ and has been uploading videos showing it in action to his YouTube channel.

The Airspy HF+ is a soon to be released low cost (expected price $149 USD) yet high performance HF/VHF receiver designed for DXing with exceptional performance in the presence of strong overloading signals. If you are interested we also have our own review of the HF+ available here.

In the video below Alexander demonstrates the HF+ on SSB and CW modes in his GQRX software. See his YouTube channel for the rest of the videos. Currently there are about 7 videos demonstrating the HF+ on his channel.

Over on his Twitter account @csete Alex has also been uploading several images of the HF+ in action as well as some screenshots of it being compared against the RFSpace Cloud-IQ which is a $629 USD SDR. So far his impressions of the HF+ seem very high.

Testing the Airspy HF+ with Gqrx, then a pirate comes by...

Simon Brown Compares the Airspy HF+ against the RFSpace NetSDR on SDR-Console V3

Simon Brown who is the author of the popular SDR-Console V2/V3 software has received an early review version of the Airspy HF+ and has uploaded some screenshots comparing it with the RFSpace NetSDR. The NetSDR is a high performance 16-bit DDC SDR with frequency range of 10 KHz – 32 MHz, and a bandwidth of up to 1.6 MHz. The base price of the NetSDR is US $1449.

The Airspy HF+ on the other hand is based on a polyphase harmonic rejection mixer design with 18-bit DDC and has a frequency range of DC – 31 MHz and 60 – 260 MHz, with a maximum bandwidth of up to 660 kHZ. It is not yet released, but is expected to be about US $149 shipped from China.

Simon’s screenshots show that despite its low cost the HF+ seems to perform just as well as the more expensive NetSDR.

If you’re interested in the HF+ we also have our own review available here.

New HF+ photo, with black metal enclosure.
New HF+ photo, with black metal enclosure.

Tuning an HF Antenna with an Airspy, SWR-Bridge and Noise Source

Over on his blog Anders J. Ørts has created a good writeup showing how he used the combination of an Airspy SDR with SpyVerter upconverter, SWR-Bridge and a noise source to tune his HF dipole for the 40 meter and 20 meter bands. If you’re interested we also have a writeup on doing something similar with the RTL-SDR here.

By connecting the output of the noise source to the SWR-bridge input, and the antenna to the DUT port the return loss or SWR of the antenna can be measured with the Airspy. To get a wider than 10 MHz view of the spectrum Anders uses the SpectrumSpy software for the Airspy which is a spectrum analyzer application that allows you to view any bandwidth that you like. With the Airspy, noise source and antenna all connected correct to the SWR-Bridge significantly notches in the spectrum show up in SpectrumSpy. These notches are the resonant points of the antenna. Visually seeing these notches allows you to fine tune the length of the antenna elements for best SWR.

How to connect it all up
How to connect it all up
SpectrumSpy showing the resonant notches at 40m and 20m.
SpectrumSpy showing the resonant notches at 40m and 20m.

SDR on an Android Wristwatch with Airspy HF+ and SpyServer

Over on Twitter @lambdaprog and @mm6dos, developers of SDR# and Airspy SDR products have tweeted videos showing off an Android watch being used as an SDR interface. They use a prototype of their upcoming Airspy HF+ SDR, their SpyServer streaming software and an Android watch. The Android watch receives the streaming FFT and audio data from a server running the SpyServer and Airspy HF+.

They write that this new SpyServer client is mainly for phones and tablets and is efficient enough to run on a watch. It appears that this lightweight version of the SpyServer sends compressed FFT and audio instead of a slice of the IQ data like the current SpyServer, making it very light on the client side CPU and network usage.

If you’re interested in the Airspy HF+ we have an initial review available here.