c$$$  main program documentation block
c                .      .    .                                       .
c main program: EXTRAT1B     time-windows, dupl-checks noaa-15 1b data
C   PRGMMR: KATZ             ORG: NP23        DATE: 1998-10-05
c
c abstract: reads in time-windowing specifications and list of noaa-15 
c   1b orbital files from standard input.  the 1b reports are then
c   read in from their separate files and checked against the time
c   window.  reports which satisfy the time window are checked for 
c   duplicates and written out to the dump file.
c
c program history log:
c   98-09-29  bert b. katz , np2  
c   01-01-24  treadon, russ, np3 -- bug fix for maximum time test
c   01-02-15  bert b. katz , np2 -- bug fix for rejection counts 
c
c usage:
c
c   input files:
c     unit 05  - standard input : namelist contains number of input 
c                files, satellite id, time-windowing specifications, 
c                line and spot sampling factors and the output file.
c                a list of tovs1b input orbital files follows the 
c                end of the namelist.
c     unit 11  - binary noaa-15 1b orbital files
c
c   output files:
c     unit 06  - printout
c     unit 51  - binary noaa-15 1b dump file
c
c   subprograms called: none
c
c   exit states:
c     cond =   0 - successful run
c          =  11 - error reading input hirs file        
c
c attributes:
c   language: cray cft77 fortran
c   machine:  cray
c
c$$$