Portsdown 4 LimeRFE Integration

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The LimeRFE is a multiband preamp and PA unit with switched filters specifically designed to be used with the LimeSDR. It can provide a useful output of 0.5 to 1W or so of DATV on all bands from 71 MHz to 2.4 GHz and slightly reduced output on 3.4 GHz. Full details are here: https://www.crowdsupply.com/lime-micro/limerfe.


The LimeRFE can be controlled from a Portsdown 4 over USB.


Configuration data for the LimeRFE is stored for each Portsdown Band. The parameters that are configured are:

  • LimeRFE Enabled/Disabled
  • LimeRFE transmit Output Port (TX/RX (1), TX (2) or HF (3))
  • LimeRFE receive attenuator setting (0 - 14 dB in 2 dB steps)

The Enable/disable and attenuator setting can be set for the current band from the Lime Configuration Menu. To select the TX output port, use the "Set Band Details" Menu.


A button is also available on the Lime Configuration Menu to change the LimeRFE to TX mode and back to RX mode to enable easy testing.

Hardware Versions

Note that the stock LimeRFE firmware always reports Hardware Version 1.6, even for Version 0.3 (early prototype) hardware. The Version 0.3 model can be modified to report correctly (which is required for proper Portsdown Operation with prototype hardware) by amending one line of the LimeRFE Arduino sketch.