The data coming from your spectrum analyzer will probably be stored and displayed in LabVIEW as an array of numbers. There is a good example that ships with LabVIEW on how to send an array of numbers to a datalog file, and also how to retrieve the data from the datalog file. You can find both the examples (Write Datalog File Example and Read Datalog File Example) in the Fundamentals->File I/O->Datalog File Examples section of the search examples window. You can search examples by going to the help menu and selecting examples.
Matt Kisler
Applications Engineer
National Instruments
http://www.ni.com/ask