TM 1-1510-218-10 3-61 3.  Pressure    altitude    (PRS)    to    the nearest 100 feet. 4.  Density     altitude     (DEN)     to     the nearest 100 feet. bc.  The Setup Pages.  (1)   The  Setup  0  Page.    The  SET  0  page  is used  for  computer  updating  of  the  database.    Update information  is  sent  on  3.5  inch  disks.    A  computer  is used    via    the    data    loader    jack    installed    in    the instrument   panel.      This   is   normally   a   maintenance function. CAUTION The     KLN     90B     does     not     perform     any navigation functions while the database is being uploaded. NOTE The disks can only be used to update one KLN   90B,   although   they   can   be   used   to update   a   specific   unit   numerous   times.   The   first   time   the   disks   are   used   in   an update  operation,  a  unique  identification code   from   the   KLN   90B   being   used   is uploaded to the disks.  These disks may be used in this specific KLN 90B an unlimited number  of  times  that  could  be  required  if switching between the North American and International  databases  occurs  during  one update  cycle.    These  disk s, however, may not  be  used  to  update  other  KLN  90B's.   This update protection ensures that Jeppesen Sanderson is properly compensated for their NavData™. (2)   The Setup 1 Page.  The Setup 1 page is used  to  manually  update  the  position  of  the  KLN  90B and enter  a groundspeed for use of the KLN 90B in the take  home  mode.    Refer  to  Figure  3-80.    Since  the KLN    90B    stores    its    position    and    other    required parameters   in   memory   when   power   to   the   unit   is removed,  it  is  seldom  necessary  to  aid  the  unit  in reaching  a  NAV  ready status.  In order for the unit to reach  a  NAV  ready  condition,  it  is  necessary  to  meet the    same    conditions    outlined    in    the    Initialization, Paragraph 3-7i. CRSR INIT POSN WPT: KMCK N 37^o 39.00‘ W 97^o 25.97’   0 KT 308^o CONFIRM? Figure 3-80.  Setup 1 Page (a)  The  KLN  90B's  almanac  data  must be current.  Almanac data is crude orbital information for  all  the  satellites  and  is  used  for  initial  acquisition when the unit is first turned on.  This data is stored in the  KLN  90B's  nonvolatile  memory  and  is  considered current up to 6 months.  Each satellite sends almanac data  for  all  satellites.    Since  the  KLN  90B  routinely updates the almanac data during normal operation, the almanac  data  will  become  out  of  date  only  if  the  KLN 90B  hasn't  been  used  for  the  previous  6  months  or longer.      Collecting   new   almanac   data   takes   place automatically  if  the  data  is  more  than  6  months  old.   This  will  usually  take  about  6  minutes,  but  no  more than 12 minutes. (b)  The  aircraft  must  be  located  so  the GPS antenna has an unobstructed view of the sky. (c)  It  is  very  helpful  for  the  KLN  90B  to have   the   correct   date,   time,   and   position.      This information is stored in the battery-backed memory of the KLN 90B, so it is not normally required to update it.   If acquisition time is not important, it is not necessary to update the date, time, and position. 1.  Select the Setup 1 page by turning the    left    outer    knob    to    SETUP, displaying a SET page annunciated     in     the     lower     left segment of the display.  Next, turn the  left  inner  knob  until  the  SET  1 page is selected. 2.  Press the left CRSR button to bring the  cursor  on  the  page  over  the WPT field. NOTE As an alternative, the latitude and longitude  of  the  present  position  can  be entered    directly    instead    of    entering    a waypoint identifier.