For the SA612/SI5351/dead bug bridge version:
The dynamic range of port 2 is limited by the leakage of the SI5351, just like the nanoVNA.
The biggest difference is above 300MHz where the directivity of the bridge becomes dependent on the quality of the layout, but below 300MHz directivity is equal to NanoVNA
For the ADF4351/IAM81008/ebay bridge version:
Dynamic range of port 2 around 2.5GHz is about 40-50dB and decreases somewhat till 30-40dB at 4.4GHz, but there no shielding at all so this can still be improved.
Directivity is ok till 2.6GHz but the ebay bridge quickly looses performance and basically stops working at 3GHz.
A SI5351/IAM81008/ebay bridge version easily has directivity till 1.2GHz, did not try higher.
