To create and IDL SAV file from a RIQ file IDL> riq_idl,'WI937_2011191140105.RIQ' This take about a minute to run Now we can run the plotting code: IDL>pulse,'WI937_2011191140105.sav' ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; To open and play with the SAV file IDL>restore,'WI937_2011191140105.sav' To see what is in the file IDL>help This prints: % At $MAIN$ MONITOR UNDEFINED = <Undefined> PCT STRUCT = -> <Anonymous> Array[1] PULSE_I INT = Array[9952, 448, 8] PULSE_Q INT = Array[9952, 448, 8] SCT STRUCT = -> <Anonymous> Array[1] You can print out ten consecutive array values IDL>print,PULSE_I[0,50:60,3] This prints rangegates 51 through 61 for the first pulse for rx 4 Or you can see what is in PCT IDL>help,pct Part of what this prints is: ** Structure <755f58>, 19 tags, length=955392, data length=955392, refs=1: RECORD_ID LONG Array[9952] PRI_UT DOUBLE Array[9952] PRI_TIME_OFFSET DOUBLE Array[9952] BASE_ID LONG Array[9952] PULSE_ID LONG Array[9952] RAMP_ID LONG Array[9952] REPEAT_ID LONG Array[9952] LOOP_ID LONG Array[9952] FREQUENCY LONG Array[9952] So you can see the frequency for a given pulse... lets do pulse 100 IDL> print,pct.frequency[99] 4108