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Welcome to the website for Zefie's RTLTCP Plugin Mod

What is it?

Zefie's RTLTCP Plugin Mod is a plugin for SDRSharp that enables a Direct Sampling via RTLTCP (which is built into the latest rtl_tcp), as well as enables support for the modified Linrad Gain modes for the E4000 chip.

Why a "Mod"?

Direct Sampling support was missing from RTLTCP at the time of the mod, and Linrad E4K modes are not officially supported by OsmoSDR (creators of RTL-SDR)

See also: rtlsdr patches, and zefie's patched rtlsdr for windows (featuring previously linked patches (including Linrad E4000 Gain Mod)) (v2, built against libusbx)


  • Source code is included, no change in license.
  • Allows enabling and disabling Direct Sampling mode from SDRSharp
  • Supports Linrad E4000 Gain Modifications (don't use this if you are not running a modified rtlsdr source)

Known Issues

  • The plugin does not check to see if the Linrad E4000 Gain Modifications are supported by the current rtl_tcp server.

Pending Feature Requests

  • None.

Special Thanks

  • prog (aka Youssef), for creating SDRSharp


  • v1.4 (Changes: Added more choices for sampling rate)
  • v1.3 (Changes: Added support for Offset Tuning)
  • v1.2 (Changes: Fixed Bugs: Update tuner gain count when setting Linrad mode, automatically enable/disable direct sampling to toggle new gain mode, focus is no longer stolen from Linrad gain mode dropdown, various other fixes)
  • v1.1 (Changes: Fixed: Disable Linrad Gain Mod Options if you switch to a non-E4000 tuner in the same SDRSharp session)
  • v1.0 (Changes: Initial Release)

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