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Macintosh Mac OS X RTL Dongle SDR Server

This app makes an RTL SDR dongle appear as a networked SDR, following the RF Space protocol. It works with SDR apps such as SdrDx. It also acts like rtl_tcp, so it can be used with Cocoa1090 and similar apps.

You can download a copy from the SdrDx page. The direct download URL is

This app requires an RTL based TV tuner with an E4000 or R820 tuner. Here are several that should work:

Basic instructions:

  • 1. Plug in your RTL device
  • 2. Run CocoaRTLServer 2.0
  • 3. Select the device from the popup menu (usually it is already selected)
  • 4. Change the rtl_tcp or tx_tcp port values if needed
  • 5. Click Open
  • 6. Configure your SDR app and run it

Recent macOS versions will likely complain they cannot open the app, try right clicking and select open.

The default port of 1234 for rtl_tcp works with Cocoa1090 and other apps that are designed to use the rtl_tcp command line app.

The default port of 50000 for tx_tcp works with SdrDx and other apps that are designed for use with an RF Space SDR like the SDR-IQ or netSDR.

If you want to change the ports, you need to quit and restart the app.

The Sample Rate and Center Frequency fields and Update button are for use if you want to manually set these values, normally they are set by your SDR app.

I've run it under Mac OS X 10.6, 10.10 and 10.11-10.13, It should run under 10.7-10.9. It only works with RTL devices with an E4000 or R820T tuner IC.

This app was based on code in "Softshell", which used code from the rtl-sdr project. Both are GPL licensed, so this is as well. A copy of the source code files are incuded with the download, most users can ignore them.

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Last November March 31, 2022