Using the Pluto+ SDR with SDRBerry via ethernet

[haywardperson]

Just to document my findings and entertain Paul while he is laid up.
It is desirable to use ethernet to connect the Pluto+ to the SDRBerry because it is more convenient to mount the Pluto+ at the masthead of the antenna rather than running coax all the way back to the shack.
The original Pluto did not have an ethernet port and the Pluto + implementation has some problems. When you first plug the Pluto+ into the RPI via USB it acts like a storage device. The config.txt file on the Pluto+ is used to configure the ethernet connection. There are some just plain mistakes in the subsection titles in this config file.

[NETWORK]
hostname = pluto
ipaddr = 192.168.1.1
ipaddr_host = 192.168.1.10.
netmask = 255.255.255.0

comments for above section^

This section is mislabeled and should read {USB-Ethernet}
This is related to a USB connection (Only when USB data port on the Pluto is plugged into your PC)
The ethernet connection is automatically created in the PC with the Pluto+ is connected via USB

[WLAN]
ssid_wlan =
pwd_wlan =
ipaddr_wlan =

[USB_ETHERNET]
ipaddr_eth = 192.168.x.x
netmask_eth = 255.255.255.0
gateway_eth = 192.168.x.254

comments for above section^

This section is NOT for a USB ethernet as indicated. It is mislabeled and should be {NETWORK}
But don't change either header just know they are labeled backwards
This is the ip address of the Pluto + ethernet. Use any ip you like for your network but not dhcp.
standard netmask for /24 networks. If you use a router/switch make a reservation for the pluto
needs to be a static ip.

When you edit the config.sys file in the Pluto+ you need to "eject" the usb device rather than just pulling the USB cable out of your computer. This causes the PLuto+ to transfer the config.txt into the PLuto+ and make the changes active.

Now you need to set a static address for your Raspberry PI ethernet port. If you are using a Raspberry Pi4 there is a bug in Trixi. If you use ifconfig eth0 192.168.x.x to set your ip address it will work for a short time and then fail. You can start pinging your Pluto+ and after about 10 successful pings it will just stop. If you start SDRBerry before it fails it might seem like the SoapyPlutoSDR driver just does not work with ethernet. But the driver autodetects the Pluto+ and always on ethernet even if your are connected USB.
So to fix this problem you need to use Network Manager ( nmtui ) to assign a static IP to the ethernet port on the RPI4. DHCP is the problem. Once the IP is stable SDRBerry works great. Be aware that running the ethernet connection throught a router/switch on the way to the Pluto+ may or may not work depending on how busy your network is with other traffic. I used a direct cable between the RPI and the Pluto +