View source for LibreSDR and the Portsdown 4

The Portsdown 4 supports transmission using the LibreSDR with the firmware supplied by DL1JM and PA2JSA.  It has been tested with firmware versions 0226 and 0326 (builds 1.20 and 1.21).

===Set-up===

The link to the firmware is available from PA2JSA.

Download the firmware and unzip to get a .img file.  Using software such as Win32 Disk Imager, write this image file to an SD Card.  Firmware versions 1.20 and 1.21 have been tested so far.

Insert the SD Card into the LibreSDR, connect it to the LAN, and apply power to the LibreSDR through the "OTG" slot.

After it has booted up, you should be able to "ping libre" from the command line of any Windows or Linux PC on the network.  This will display the IP address of the LibreSDR, which you can then enter into a browser to read the documentation.  However, this step is not necessary for use with Portsdown.

To use with the Portsdown, simply update the Portsdown to the latest development version (you may need to do a normal update to the latest production version before this option becomes available), and then select "Output to" on Menu 1.  If the Portsdown can see the LibreSDR on the network, the LibreSDR button will be blue.  If it is grey, it means that the Portsdown cannot see the LibreSDR on the network and some investigation will be required.

It is possible to set a specific IP address on the Portsdown for the LibreSDR.  To do this, go to "Menu 3", select "Pluto and Libre Config", and then set LibreSDR IP Address.  The default value is dhcp, which looks for the LibreSDR on its default name of libre, however a network address can be inserted here instead.

It is not possible to use a USB connection between the LibreSDR and the Portsdown - only LAN connection is supported.

Select Libre SDR as the Output device on Menu 1.  Operation is very similar to the Pluto.  Only H264 video encoding is supported and the frequency limits are from 70 MHz to 6 GHz.  Power can be adjusted from the LibreSDR power button on Menu 1, in the range 0 to -30 (approximately dBs).  Power selections below -30 do not seem to result in reliable transmission.  The stored power setting is also used for Pluto transmissions.

Further work is required to get the LibreSDR using this firmware to work with BandViewer.

Thanks to DL1JM and PA2JSA for this excellent firmware.