Just showing the ground plane on the Ethernet/Wifi Hat. I am very pleased with this one and the approach I used here. Earlier as I routed I have routed on both sides with ground plane becoming very fragmented. On this one I only used ground plane as an exception and only for minimum distances. The cost is that I go forth an back a little, but the result was a much better ground plane with no fragmentation of areas.
I feared routing Ethernet would be difficult an result in a very fragmented board, but it has actually gone much smoother than expected and with a very good ground plane as result.
I do however keep promissing myself to move to 4 or 6 layer PCB’s once I have the prototypes working. I don’t need extra layers for routing, I need extra layers for EMC and noise reductions as I start penetrating higher frequency signals. But, well – if this works on 10Mbps and not on 100Mbps we know the reason and how to fix it. I will annotate the new Hat later.