I am in the process of updating Solver's user manual and repeated the PDN measurements with my H4 using the latest firmware available. I had no lockups or glitches in the data.
I had damaged my H4 (suspect ESD) and when repairing it, I had added a few additional caps which greatly improved the noise floor at higher frequencies. Still, it is not good enough to resolve 100uOhms.
Link to troubleshooting, mods and performance gains of my H4.
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg5695349/#msg5695349I also have the newly release LiteVNA hardware. I was very much surprised that it performs slightly better then my other low cost VNAs at these lower impedance's, however it is still not able to resolve 100uOhms.
That said, typically when I run into problems with emissions, they are in the several MHz on up past GHz. Assuming you are wanting to measure the PDNs stability for emissions, how do you test it at these higher frequencies? Or is it not a concern?