I just want to clarify something for anyone who comes to this page trying to determine if they can read out unwrapped phase from the E5071C analyzer. The answers above regarding the SNP file format are accurate, but if you are willing to get the data through SCPI commands you can. You can read unwrapped phase from the analyzer. For example, to get unwrapped phase for S21 s-parameter, channel 1...
# create s-param
# pick unwrapped phase format
# get frequency data
# get unwrapped phase data...remember to ignore every other value, since you are not collecting two pieces of
# information as the same time, so every other value is always zero and not of interest
I have tested this and compared against the measurements displayed on the analyzer screen and have verified they are the same. This means you do not have to create a function to try to unwrap phase, which is a nightmare better left to the network analyzer.
Retrieving data ...