Quick start guide

Installation on Windows Vista, 7, 8, 8.1 and 10

Airspy is a plug-and-play device and does not require any particular driver installation on Windows Vista, 7, 8, 8.1 and 10. You just plug Airspy and Windows will download and install the right driver for you.

Plug & Play

There are exceptions where the original configuration of the PC does not allow the automatic installation of this class of devices. In such case, a driver should be installed manually with the following procedure:

  • Download and unzip the WinUSB Compatibility Driver
  • Open the device manager and select Airspy
  • Select “Update Driver” then “Browse My Computer” to the inf file

Installation on Windows Server or Windows XP

Please don’t. They are not supported.

Using SDR#

Airspy was designed by the same people who developed the SDR# software so it’s the obvious choice for running Airspy and leverage all its powerful features.
First, go to the download page and get a copy. Then run SDRSharp.exe and select the “AIRSPY” front-end:

SDR# Airspy One option

Then next step is the gain configuration. As depicted in this screen shot, there are many gain modes:

  • Sensitivity
  • Linearity
  • Free (Custom)

The “Linearity” mode is the one you want to start with:
Airspy in Linearity mode

The following fine tuning procedure ensures you have the maximum SNR on the signal of interest while preserving the dynamic range:

  • Start with the minimum gain
  • Increase the gain until the noise floor rises by about 5dB
  • Fine tune to maximize the SNR (the blue bar graph on the right)

Airspy Best SNR

In any case, you should make sure the RF noise floor just overrides the quantization noise floor of the ADC, but no more.

Using the SpyVerter

Airspy has an option to cover the HF bands: The SpyVerter. It is a low loss, high dynamic range, ruggedized up-converter based on a switching design – the same kind that is used in very high end HF rigs like the Elecraft K3. It offers HF coverage starting near DC up to 35MHz where it overlaps with the standard VHF-L of the Airspy alone. The default software settings allow Airspy to power the SpyVerter via the bias-tee functionality so no extra power supply is needed. Just connect the “IF Output” of the SpyVerter to the RF Input of the Airspy via the supplied barrel adapter.

It is recommended to use the Linearity gain mode in HF.
SpyVerter Markings
To verify your setup, plug a HF antenna and tune the AM broadcast band. You should get a view like this one:
SpyVerter VLF LF LW MW

Using the ADSB decoder in embedded ARM boards

Prerequisite

You need firmware version 1.0 rc7 or newer to use Airspy as an ADSB receiver. Get the latest update from here:
https://github.com/airspy/firmware/releases
READ the instructions before doing anything.

Standard setup (non FlightAware)

The whole process for setting up a high performance ADSB receiver has been simplified. For the Raspberry Pi 2 or 3, Odroid or Pine64 boards, you can use the following commands:
mkdir airspy
cd airspy
wget http://airspy.com/downloads/airspy_adsb-linux-arm.tgz
tar xzf airspy_adsb-linux-arm.tgz
sudo ./airspy_adsb -l 30005:beast -l 47806:asavr -c sdrsharp.com:47806:avr -p -n -w 4 &

FlightAware Integration

The easiest way to integrate Airspy into an existing FlightAware PiAware system is to feed dump1090 through its “MLAT result” port.
mkdir airspy
cd airspy
wget http://airspy.com/downloads/airspy_adsb-linux-arm.tgz
tar xzf airspy_adsb-linux-arm.tgz
sudo ./airspy_adsb -c localhost:30104:beast -c sdrsharp.com:47806:avr -p -n -w 4 &

Operation

Once you have your decoder up and running, you can use any aircraft tracking software that supports the Beast or AVR formats.

Virtual Radar Sever

Here’s an example configuration for Virtual Radar Server:
Airspy + RPi 2 + VRS

Plane Plotter

For Plane Plotter, you can use this configuration:
Plane Plotter Configuration 1
Plane Plotter Configuration 2

The effects of oversampling and decimation

The decimation option allows you to trade some of the instantaneous bandwidth to get more bit resolution, and hence, lower quantization noise. The basic rule of thumb is 3dB every time you divide the bandwidth by two. So, decimation by two gives you 3dB, decimation by 4 gives you 6dB, by 8 gives 9dB and so on.
To further leverage the effects of the decimation, you can also readjust the gain using the same procedure described above. A slight saturation of the ADC gives you more SNR after decimation. So basically, when you use a higher decimation rate, adjust for higher gain and vice versa.

The Bias-Tee option: 4.5v @ 50mA

In some cases, one may need a very low noise figure. For example, some satellite communication systems require a front end with a noise figure as low as 0.2dB. In such case, using an external preamplifier near the antenna system can improve the overall operation. The Bias-Tee option allows powering such a preamplifier directly from Airspy by injecting DC at 4.5v. Of course, such a preamp should have its own biasing system to extract the DC and inject the amplified RF signals. The current budget is limited to 50mA, so that’s enough to run most of the modern MMICs.
Another use case one can imagine is to switch between antennas using that bias signal or even power down-converters for higher bands OR up-converters for LF and HF, like the SpyVerter mentioned above.

Calibration

Starting from June 2016, Airspy R2 units are calibrated in the factory up to ~0.05 PPM. This calibration is written in a different memory location than the one used for the firmware, so upgrading the firmware won’t delete it unless you do it by yourself.
The procedure to recalibrate a unit is as follows:

  • Open the calibration tool (AirspyCalibrate.exe),
  • Clear the correction,
  • Reset the device (unplug/plug again),
  • Inject a known and accurate signal,
  • Set its exact frequency in the tool,
  • Click on “Calibrate”,
  • Reset the device.

Note that this procedure requires firmware version 1.0-RC9 or better.

Troubleshooting PC performance problems

We created a set of command line utilities to help troubleshooting the performance problems.

  • Download the latest release of the tools package
  • Open a console (cmd.exe) and run airspy_rx -r NUL -t 0
  • Leave it running for 30 seconds, then Ctrl+C
  • If the average throughput is below 10.0 MSPS then either your USB controller has problems or you CPU can’t process the data. Possible solutions:
    • Use another USB port
    • Update your USB drivers (Prefer OEM drivers to generic ones)
    • Check your anti-virus or any other CPU heavy task
  • See also our Wiki: https://github.com/airspy/host/wiki/Troubleshooting (users can update it with their configuration/solutions)

Known issues

  • Slow computers won’t be able to run Airspy at 10MSPS without dropping samples. That’s a lot of data to process in real time. Make sure you run Airspy in a modern machine as described in the minimum hardware requirements.
  • In a fresh Windows 7/8/10 installation, Windows Update will grab the generic Microsoft USB drivers. These may not be optimal for high throughput operation and it is advised to update them with the latest version from your OEM. For example, the latest Intel USB 3.0 drivers turned the streaming on some PCs from choppy to perfectly smooth.
  • Some old generation USB 3.0 controllers are not compatible with USB 2.0 devices at high speed. Changing the USB port can be sufficient to solve this problem. And again, make sure you run Airspy in a modern machine as described in the minimum hardware requirements.
  • In some PCs, the experimental 2.5MSPS mode is vulnerable to USB noise. This will be improved with further firmware updates. The recommended method to get lower sample rates is to use some decimation with the 10MSPS stream.
  • USB Hubs won’t work at the full sampling rate. Just don’t use them.
  • Beware of overheating. Keep your unit in open air environment while running.

 

That’s all folks!