c$$$  main program documentation block
c                .      .    .                                       .
c main program: EXTRTV1B     time-windows and dupl-checks tovs1b data
C   PRGMMR: KATZ             ORG: NP2         DATE: 1998-04-30
c
c abstract: reads in time-windowing specifications and list of tovs1b 
c   orbital files from standard input.  the tovs1b reports are then
c   read in from their separate files and checked against the time
c   window.  reports which satisfy the time window are checked for 
c   duplicates and written out to the dump file.
c
c program history log:
c   98-01-20  bert b. katz , np2  
c   98-04-10  bert b. katz , np2 -- code is now y2k compliant
c   98-04-27  bert b. katz , np2 -- year, month, day separated to 
c                                   achieve true y2k compliance.
c                                   converted to fortran 90 to use
c                                   kind parameter for long integers
c                                   in date comparisons.
c   01-01-24  treadon, russ, np3 -- bug fix for maximum time test
c   01-02-15  bert b. katz , np2 -- bug fix for rejection counts 
c
c usage:
c
c   input files:
c     unit 05  - standard input : namelist contains number of input 
c                files, satellite id, time-windowing specifications, 
c                line and spot sampling factors and the output file.
c                a list of tovs1b input orbital files follows the 
c                end of the namelist.
c     unit 11  - binary tovs1b orbital files
c
c   output files:
c     unit 06  - printout
c     unit 51  - binary tovs1b dump file
c
c   subprograms called: none
c
c   exit states:
c     cond =   0 - successful run
c          =  11 - error reading input hirs file        
c
c attributes:
c   language: cray cft77 fortran
c   machine:  cray
c
c$$$