Cloud-SDR Client

Table of content:

foreword : The Cloud-SDR client application (cSDRc) is a free software defined radio (SDR) receiver supporting local or remote radio devices. It is the natural companion of the SDRNode streaming server software but can also be used independently. 



Cloud-SDR client is designed to work with remote SDR streams coming from SDRNode software but also accepts locally connected SDR hardware.


Cloud-SDR client is similar to many existing SDR receiving software but comes with very specific features making it unique:

  1. Dual channel receiver: RXA and RXB are two totally independent receivers;
  2. Geographic integration: Display on map beacons, ADS-B reported airliners, known HF broadcast stations or any geo-localized information coming from the SDRNode server;
  3. GPS compatibility: plug a GPS receiver to your computer and track your location on the map, record signals with your position for later processing (coverage mapping etc.); display the UTC time;
  4. Digital Terrain Elevation: See the terrain elevation around your position, or in the direction of the antenna directly on the map (requires to download the free SRTM3 files from NASA, with 90m resolution);
  5. MP3 audio recording: record to mp3 the demodulated streams to reduce disk requirements;
  6. Chat with other users connected to the SDRNode Group: when used as a remote client for the SDRNode streaming server, you can interact with other users with messages or station spotting;
  7. Time-domain analysis: the MSR mode enables analysis of any sub-band and displays in real time the time domain signals of the selected spectrum portion. This sub-band can also be recorded (with geographic position if GPS is connected) and processed with provided MATLAB®.

Languages :

  • Currently interface is available in English or French, language detection is made on startup depending on your computer configuration.
  • If you want to help and make the translation for your language, feel free to contribute and contact us.

cSDRc is written in C++ and uses the Qt framework. The different processing blocks are working as independent tasks consuming blocks of IQ samples from an incoming FIFO and producing their output to the next chained block, similarly to what is done in GNU Radio.

The following software have been source of inspiration and are partially included in this work:

  • CuteSDR from Moe Wheatley, thanks for his work and excellent documentation.From his original code we reused the Fractional Resampler and the downconverter (with some fixes from gqrx)
  • Waterfall display + freq selection taken from gqrx (, by Alexandru Csete OZ9AEC
  • Map display from
  • WGS84 code is Copyright (C) 2006 Mathias Froehlich –
  • Spectrum display and buttons are based in part on the work of the Qwt project (
  • FM demodulator comes from Liquid-SDR ,, from Joseph D. Gaeddert.

For more details on the included software libraries, please check the Licenses folder of your cSDRc installation.

Supported hardware

The following SDR receivers drivers are currently available:

  1. SDRNode remote server,
  2. RTLSDR,
  3. AirSpy (1; R2 and Mini)
  4. BladeRF (x40 and x120);
  5. SDRPlay (1 and 2);
  6. PerseusSDR.

The different drivers for local hardware are open-source and available on our Github repository.


Like other Cloud-SDR software, support is provided through the community forum:

Getting and installing Cloud-SDR Client

To get the software installer for the free Cloud-SDR client go to and create your account.

After successful registration, log in and go to the Downloads page :

Depending on your system, now download and run the CSDR W64 Install.exe or CSDR W32 Install.exe file. You will get the following window:


Then select the destination folder:


Select the various optional modules you want to install :


Note : EXTIO option is only needed if you want to access remote SDRNode published streams with other SDR client software like HDSDR.


SDR receivers configuration

For the SDRPlay receivers, you must install the drivers published from the company website ( :


make sure you select the API/HARDWARE DRIVER 2.09. If you already have installed a previous version of the drivers, you have to update your setup because of important changes that make the older drivers not compatible with current version of the SDRPlay driver.

For other receivers (RTLSDR, AirSpy, BladeRF, …) you need to use ZADIG Usb configurator as follows:

  1. Plug your hardware device in your PC
  2. Start Zadig
  3. Search for the device in the combo box
  4. Install/replace driver with WinUSB (libusb)


When your SDR hardware is correctly configured, it should appear – when connected – under the “Universal Serial Bus devices” item in the Device Manager, as shown in the following :


Running the Cloud-SDR client

After successful installation, a new menu entry should be available, for example :


Click. On startup, the Cloud-SDR client application will launch the different drivers you selected during the installation, each trying to locate available devices. For example if you have RTL-SDR USB dongle (note the Local info displayed in the Type column):


You can change the bandwidth/sampling rate from the “sampling rate” selection widget :


Then click “Use RTL820T” or “USe xxx” depending on the hardware you want to use. That’s it !

Troubleshooting : if your hardware is not listed in the “select hardware” window, make sure you have installed the relevant drivers, make sure you configured correctly Zadig (except SDRPlay). You can also chek the community forum and post a support request message.

The main application screen now displays and you can use the control-bar to start/configure your receiver :


Add terrain elevation

This feature is very useful when you plan your field days : check where the land is good for VHF and above !

Cloud-SDR Client is compatible with the NASA SRTM 90 database. Check this website for more details on the dataset :

To have the terrain displayed in the “map” tab of your Cloud-SDR client, proceed as follows:

Browse to :


Click on the tiles you want to have (mind your disk free space… whole world is several Gb). After successfull download, unzip the files into the SRTM3 subfolder in your Cloud-SDR Client installation:


You now have to edit your client configuration file (conf/cloud-sdr.conf) to say where you have the files:


your station location is defined by the lon, lat coordinates (in degrees). You can also change your location by dragging the antenna object on the Map tab.

Airport and airfield frequencies publishes (on this page) files giving many updated information on the airport location, frequencies etc. The Cloud-SDR client can read the csv files and display them on your map tab, making it easy with the mouse to clic and tune.

You need to download the following two files (save them for example in the db/ subfolder) :

You can integrate these lists as follows by changing your client configuration file (conf/cloud-sdr.conf) as follows:


The Cloud-SDR client keeps only airports who have at least one frequency in the “frequency set” file.

To learn how to use the Cloud-SDR client software, check the following YouTube videos :