TM 1-1510-218-10 3B-10 1.  FREQ Display 2.  Mode Display 3.  CHANNEL Display 4.  Light Sensor 5.  MODE Button 6.  FREQ / CHAN Button 7.  PGM (Program) Button 8.  Frequency/Channel Selector 9.  STO (Store) Button 10.   OFF / VOLUME Control 11.   SQUELCH Control 12.   CLARIFIER Control Figure 3B-4.  HF Control Panel (6)   FREQ / CHAN Button.  Transfers the HF system    from    a    direct    frequency    operation    to    a channelized form of operation. (7)   PGM Program Button. Enables channelized data to be modified.  The PGM message will be displayed whenever this switch is pressed. (a)   Program.    The  program  mode  must be  used  for  setting  or  changing  any  of  the  99  preset frequencies.    Each  of  the  99  channels  may  be  preset to receive and transmit on separate frequencies (semi- duplex),  receive  only,  or  transmit  and  receive  on  the same frequency (simplex).  The operating mode (LSB, USB  or  AM)  must  be  the  same  for   both  receive  and transmit and can also be preset. (8)   Frequency/Channel Selector. This selector  consists  of  two  concentric  knobs  that  control the   channel   and   frequency   digits,   plus   the   lateral position of the cursor. (a)   Frequency  Control.    The  outer  knob becomes   a   cursor   (flashing   digit)   control   with   the FREQ   /   CHAN   switch   in   the   FREQ   position.      The flashing   digit   is   then   increased/decreased   with   the inner knob. (b)   Channel  Control.    The  outer  knob  is not functional when the  FREQ / CHAN switch is in the CHAN  position.    The  inner  knob  will  provide  channel control from 1 through 99, displayed at the right end of the display window. (9)   STO Button.  Stores displayed data when programming preset channels. (10)   OFF  /  VOLUME  Switch.    Applies  power to the unit and controls the audio output level. (11)   SQUELCH.      Provides   variable   squelch threshold control. (12)   CLARIFIER.    Provides  250  Hz  of  local oscillator adjustment. c.    Operating Procedures. NOTE The  mode  for  each  channel  (LSB,  USB,  or AM) is stored along with the frequency.  If the    mode    is    changed,    the    system    will receive  and  transmit  in  the  mode  selected for transmit. (1)   OFF / VOLUME Switch.  Turn clockwise out of OFF position.  Adjust volume as desired. (2)   Frequency     Operation     (Simplex     Only). Each digit of the frequency may be selected instead of dialing    up    or    down    to    a    frequency.        The    larger concentric   knob   is   used   to   select   the   digit   to   be changed.  This digit will flash when selected.  Rotation of the knob moves the flashing cursor in the direction of  rotation.    After  the  digit  to  be  changed  is  fl ashing, the   smaller   concentric   knob   is   used   to   select   the numeral  desired.    This  process  is  repeated  until  the new frequency has been selected.  The flashing cursor may then be stowed by moving it to the extreme left or right  of  the  display  and  then  one  more  click.    This stows   the   cursor   behind   the   display   until   needed again.      The   cursor   may   be   recalled   by   turning   the concentric knob one click left or right.