Connecting the ADALM-Pluto using Ethernet

I want to try controlling the Pluto from Portsdown4 and Langstone via Ethernet rather than USB.

I obtained an Ethernet-to-USB 3.0 adapter and a short USB Micro male to USB female adapter lead. Here is the Ethernet-to-USB 3.0 adapter.

This is the USB Micro male to USB female adapter lead:

The USB Micro male plugs into the Pluto, the USB female connects to the Ethernet-to-USB 3.0 adapter.

With the Pluto connected to the Linux PC directly via the usual USB cable, I opened the Pluto mass storage “drive” on the PC. I edited the config.txt file with gedit.

I edited ipaddr_eth to be my chosen IP address for the Pluto and gateway_eth to the address of my router. Note: it is not advised to have the Pluto on the same sub-net as the internet connection, so I intend to change this later.

[USB_ETHERNET]
 ipaddr_eth = 192.168.1.52
 netmask_eth = 255.255.255.0
 gateway_eth = 192.168.1.1

I removed the USB cable and connected the Ethernet-to-USB 3.0 adapter USB to the Pluto. The adapter uses an RTL8153 chip. I connected the Ethernet-to-USB 3.0 adapter to the network with an Ethernet cable (the yellow cable in the picture) with RJ45 plugs. The Pluto also had a Power Supply feeding it.

I was then able to ping and also browse the Pluto at 192.168.1.52, so the Pluto’s Ethernet connection seemed to be working.

On the Linux PC, putty connected to the Pluto fine. So all looked well. However…

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Update 14-April-2021: the above cabling proved unreliable. It stopped working. In case I had blown the ethernet adapter, I tried another, RTL8154 based, adapter. This worked and then didn’t. It too was unreliable.

I had found Matthias DD1US’s post about connecting an ethernet adapter to the Pluto using a Y cable. The article didn’t really explain why a Y cable might be necessary.

I had thought that the Pluto would easily supply the 40mA or so of DC to the ethernet adapter and it did do this, but I found that most of the time, the Pluto ignored the ethernet adapter.

After seeking advice on the BATC forum, Mike M0MJW suggested I should use a Y cable. It does seem to work. This below, is the arrangement I tried today. The grey plug, bottom right, supplies the DC power. The Pluto seems to run happiest at 4.9V (see Powering the Pluto). The DC is then fed via the Y cable to both the ethernet-USB adapter (the black case in the middle of the picture with the yellow ethernet plug) and to the Pluto via its USB port. The Pluto then finds the adapter. There is nothing plugged into the Pluto’s DC socket:

The yellow Ethernet cable runs to the Portsdown 4/Langstone box some meters away.

I was able to ping the Pluto at 192.168.1.52 from a PC on the network.

I tried Langstone and the software found the Pluto and showed a waterfall screen.

The Portsdown M2/Info screen showed its IP as 192.168.1.51 . I tried Portsdown transmitting a testcard and this produced RF power out from the Pluto. I could receive the picture across the bench on MinTioune software.

So the more complicated arrangement with the Y cable works OK. My Y cable has USB3 A-type connectors and so I had to add a USB A female to USB Micro female adapter so that I could plug in the power supply lead. Having a separate DC supply for the Pluto also means that it can receive its preferred 4.9V, not the 5.1 to 5.2V preferred by the RP4.

Portsdown4 + Langstone video

I moved the new Raspberry Pi 4 into the Portsdown box and used the Portsdown functions to upgrade both Portsdown and Langstone software versions to their latest versions. Via putty, I ran set_sound to select my “3D Sound” audio dongle. I fed the output to the speakers in the box via a little audio amplifier.

Here is a video of switching from Portsdown to Langstone and back. Langstone was still tuned to the GB3KEU beacon on 6cm or thereabouts, but there was no RF input to the Pluto.