TM 55-1510-220-10 (7) 0.025     MHz     selector.          Selects     receiver- transmitter  frequency  in  0.025  MHz  increments.  Clockwise rotation increases frequency. (8) 0.025   MHz   indicator.      Indicates   manually selected     receiver-transmitter     frequency     in     0.025     MHz increments. (9) Preset CHAN selector.  Selects preset channel from 1 to 20.  Clockwise rotation increases number selected. (10) Preset   CHAN   indicator.      Indicates   selected preset channel. (11) LOCKOUT    FM-AM    switch.        Screwdriver adjustable  three-position  switch.    Warning  tone  announces lockout when tuned to a frequency in the locked out band. (a) Center.  Selects AM or FM band. (b) AM.  Shuts off AM band. (c) FM.  Shuts off FM band. (12) FM SQUELCH control. Screwdriver adjustable  potentiometer.    Squelch  fully  overdriven  at  full counterclockwise position.  Clockwise rotation increases input signal required to open squelch. (13) WB-NB-MEM  LOAD  switch.    Three-position switch. (a) NB.    Limits  selectivity  to  narrow-band intermediate frequency. (b) WB.      Limits   selectivity   to   wide-band intermediate frequency of FM band. (c) MEM   LOAD.      Momentary   switch.   If pressed, loads manually selected frequency in preset channel memory. (14) AM SQUELCH control. Screwdriver adjustable  potentiometer.    Squelch  fully  overridden  at  full counterclockwise position.  Clockwise rotation increases input signal required to open squelch. (15) Mode  selector  switch.    Three-position  rotary switch. (a) OFF.  Shuts off receiver-transmitter. (b) TR.  Selects transmit/receive modes. (c) DF.  Not used. (16) SQ-DIS-TONE  select  switch.    Three-position switch. (a) Center.  Selects squelch function. (b) SQ-DIS. Shuts off squelch function. (c) TONE. Transmits tone of approximately 1000 Hz. (17) Frequency   control/emergency   select   switch. Three-position switch. (a) PRE.  Enables preset channel selection. (b) MAN.  Enables manual frequency selection. (c) EMER-AM-FM.  Selects a prestored guard channel. (18) VOL     control.          Clockwise     rotation increases volume. c. Normal Operation. (1) Turn-on   procedure:      Mode      selector switch (VHF AM-FM control panel, fig.  3-5) - TR. NOTE SATCOM/FM audio selector switch must be set to FM . (2) Receiver operating procedure: 1. Frequency  control  emergency  selector switch  (fig.    3-5)  MAN  or  PRE,  as desired. 2. Transmitter-interphone selector switch (audio  control  panel,  fig.    3-1)  No.2 position,    or    radio    monitor    control No.2ON. 3. Manual frequency/preset channel selectors Set desired frequency. 4. Volume control As required. Change 2 3-12