function f_name = get_file_list_bytimespan( start_time, end_time, ...
                                                        dir_type, band, mytype);

% Uses a start_time and end_time to find the full list of path/file
% names for all scan types under the directory structure used for
% S-Pol CfRadial data.  This routine uses get_sorted_file_list to find
% a full day of scans, concatenates days, then trims the start and end
% of the file list to match the desired start/end times.
%
% The routine requires that the start/end times are strings in the
% form 'ccyymmddhhmmss'.
%
% Remember that, within the S-PolKa scheme, scans are grouped first 
% by type of data (moments, covars, or whatever), then by 
% s or x band, then % by scan type.
%
%  f_names = get_sorted_file_list('20110411120000','20110411175900',
%  'moments', 'sband');
%
% or 
%  f_names = get_sorted_file_list('20110411120000','20110411175900',
%  'moments', 'sband', {'sur'; 'sec'});
%
% Note that the get_sorted_file_list routine requires that a global
% root directory be set, but that this routine does not require
% that global variable.

% global rt_direc;   % /export/d2/rilling/DYN_test/cfradial

% Sanity checks on input times:

if( length(start_time) ~= 14 || length(end_time) ~= 14 );
    fprint(['Input Time values do not have correct length in ' ...
            'get_file_list_bytimespan\n']);
    fprint('Aborting.\n');
    return;
end;

entm = datenum(end_time,'yyyymmddHHMMSS');
sttm = datenum(start_time,'yyyymmddHHMMSS');

if( sttm >= entm );
    fprint('Start time is greater than or equal to end time.\n');
    fprint('Aborting\n');
    return;
end;

start_date = start_time(1:8);
end_date   = end_time(1:8);

f_name = [];
my_date = start_date;

while ( my_date <= end_date );
   fn = get_sorted_file_list( my_date, dir_type, band, mytype );
   f_name  = [ f_name; fn ];
   my_date = datestr((datenum(my_date,'yyyymmdd') + 1), 'yyyymmdd');
end;