When using Sentinel to measure a 5G (NR) OTA signal, you may need to enter the SS/PBCH Block Pattern value, depending on the Frequency Selection method used:
The SS/PBCH Block Pattern is entered as a Case. These Cases are defined in section 4.1 of 3GPP TS 38.213, and each specifies the location of the Synchronisation Signal Block start symbol within the transmission as per the table below:
Sentinel uses the location of the first SSB start symbol to measure the time error of the 5G OTA signal relative to its reference (e.g. GNSS).
Using the incorrect Case value can affect the accuracy of the results. For example, Cases B and C both use the same SSB subcarrier spacing of 30 kHz but selecting the wrong case will result in a measurement offset of approximately 70μs. Using the correct configuration is therefore essential for valid measurement.
See https://uk.mathworks.com/videos/5g-explained-synchronization-signal-blocks-in-5g-nr-1577445332091.html for more information on 5G Synchronisation Signal Block Pattern Cases.