Introduction to Remote SDR

Web based Transceiver

“Remote SDR” or “SDR Distant” is a web application allowing to remotely control an amateur radio transceiver between 1 MHz and 6 GHZ. Its first application was the duplex control of a station allowing links to the geostationary satellite QO-100 / Es’Hail 2.

Short presentation of Remote SDR 4.2


The key point of Remote SDR is to be able to locate the RF processing close to the antenna so as not to be penalized by losses in the feed coaxial.

QO-100 Transceiver of F1ATB


An SDR like the Pluto requests 1.4 M samples / s (minimum) * 2 Bytes (16 bits) * 2 channels (I and Q) = 5.6 M Bytes / s for reception. The same is true for the transmission. Which gives us more than 10M bytes / second.
With Remote SDR, output on Ethernet or WiFi requires:

  • 10 k samples / s * 2 bytes for the audio in reception
  • 10.24 k sample / s * 2 bytes for the reception spectrum
  • 10 k sample / s * 2 bytes for transmit audio
    We are at less than 100 k bytes / s by adding the control data.

There is therefore a reduction of approximately 100 in the communication flow required, which facilitates remote control via internet / ethernet without loss of quality through data compression.

Remote Single Board Computer

Indeed, we have a remote single board computer which has a GPIO to which it is possible to add functions. For example, piloting an antenna rotor, measuring electrical voltages, temperatures, etc., etc. Likewise, the system can be accessed via the web (Apache server), in SSH to launch an application in terminal mode, or in mode graph by desktop and VNC.

3 thoughts on “Introduction to Remote SDR”

  1. Great software, but having just changed my LNB crystal I need to change the QO100 Offset frequency.
    I assumed it was in the RX .js file but changing this does not seem to make any difference?
    Can you help please?

    1. You have to change that in the configurationRX.js file.
      If you did it and it doesn’t change, it’s the issue with the cache memory of your browser. The browser don’t reload the new file, but continue to work with the old one.
      CTRL-F5 2 or 3 times can solve the issue.
      If it still not work. Put a lot of empty lines in the file and may be the browser will see the difference.


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