I needed an easy way to adapt BNC to banana. There are plenty of M < > F adapters out there, but I wanted something I could put on my bench and plug cables of different lengths into.

I came up with this simple PCB. The only design consideration was that the BNC is grounded but the Banana jack isn't. To solve this I allocated a ground terminal to each jack, with a corresponding jumper block or, if you move a jumper block to the back, dual wirepads for ground that any or all of the 3 banana jacks can share.

Each banana jack is paired with two nearby ground wirepads. The wirepads are 5mm apart, so you can use standard 5mm screw terminal blocks, as in the photos for this project, a conductive wire loop if you want to use gator clips to a ground on your bench, or whatever other option works for your bench setup.

As far as the BOM: The jacks and blocks used in the project, if sourced from a name brand manufacturer like Amphenol, are quite expensive, so I also include a word BOM docx file with links to clones on Amazon that work and are more affordable.