Version 3



This is the On-Air website for's publicly available servers. You can add your own radio to the list by following the Server Configuration instructions, or you can listen to one of these servers with the Console by following the Listening instructions. 

This product includes GeoLite2 data created by MaxMind, available from




When your server connects to the On-Air service an access check is performed by the On-Air service to check that the server can be accessed correctly. The On-Air service connects to the port number defined in the server's network pane (this port is usually 50101). If this check fails a warning icon is displayed; the reason why the check fails is most probably a firewall blocking the server's port. If the On-Air service cannot connect then the console will not be able to connect. 

Timeout after x seconds

The on-air service did not receive any response at all from your server - either the port is forwarded to a non-existent address or a Firewall is running and has not allowed access to the port.

Port forwarding problems can happen your server's address has changed after a restart, so assign a fixed address in your router's DHCP configuration.

Connection refused

Access to the server port is either blocked by your router (check the port forwarding) or a firewall.

Error 10054 Connection Reset By Peer

This error message is returned when your WAN (internet) access is blocked by the firewall in the Server Manager. If there are any whitelist (allow) entries then your public (WAN) IP must be in the list.

Audio Stuttering

This software uses an internal buffer to ensure the remote data (IQ) is streamed without breaks if your internet connection slows down or is interrupted. When you start the remote radio the buffer will start to fill; when it reaches the buffering level (usually 100ms) the radio starts displaying the data in the waterfall and audio will be heard. If the buffer becomes empty due to an interruption in the network the above logic is applied again - it is preferable to have fewer breaks like this. The suggested value is 100ms - only if you are suffering from a very erratic network connection should you need to increase this value.

Server Localtime

Adding A Server

Full information is available on the main website.




To use these SDR radios you must download and install version 3.0 Beta 1 or higher. Beta 1 will be available on February 10th 2018.

To display this list in the console:

  • Open Select Radio from the ribbon bar
  • Select Definitions
  • Search for V3 Server (bottom of the list)
  • Select SDR Space in the Autodetect window.


  • Port (usually 50101) forwarded to computer where the server is running (router settings)
  • IP address of server's PC has not changed (network properties)
  • Firewall on router allows incoming TCP connections on port (usually 50101)
  • Firewall on server's PC allows incoming TCP connections on port (usually 50101)
  • After making changes it can take one or two minutes for the on-air display to be updated, alternatively restart the service.

On-Air Address

The on-air address is:

  • Address =
  • Port = 50199
  • Code = WelcomeV3

The Technology

The On-Air server is a standard Windows service running 'somewhere' in the world of the web (usually Falmouth, Cornwall). The SDR server connects to this service and sends regular updates every 5 seconds. The service collates this information and creates XML (for the Home page) and KML (for the Map page) files at regular intervals, usually every 5 seconds.

The XML file uses XSL to format the data on the Home page (XSL stands for EXtensible Stylesheet Language, and is a style sheet language for XML documents - see for more information).