TM 1-1510-218-10 3A-6 (c)  BOTH. Selects main receiver, transmitter, and guard receiver. (d)  ADF.          Selects     ADF     or     homing system, if installed, and main receiver. c.   Normal Operation. (1)   Turn On Procedure. 1.   Function  selector  switch,  UHF  control panel – BOTH. (2)   Receiver Operating Procedure. NOTE The PRESET  channel selector and manual frequency  selectors  are  inoperative  when the MANUAL / PRESET / GUARD switch is set to GUARD. 1.   Function selector switch – As required. 2.   Frequency – Select required frequency  using  either  preset  channel control  or  manual  frequency  selector controls. 3.   Volume – Adjust. 4.   SQUELCH – As required. (3)   Transmitter Operating Procedure. 1.   Transmitter    selector    switch    –    UHF position. 2.   Microphone switch – Press. (4)   Shutdown Procedure. 1.   Function selector switch – OFF. d.  Emergency Operation. NOTE Transmission  on    emergency   frequencies (guard    channel)    shall    be    restricted    to emergencies only. An emergency frequency of 121.500 MHz is also available on the VHF command radio set. 1.   Transmitter    selector    switch    –    UHF position. 2.   Mode selector switch – GUARD. 3.   Microphone switch – Press. 3A-8.  UHF COMMAND SET (AN/ARC-164 HAVE QUICK). a.   Description.    The  UHF  command  set  is  a line-of-sight radio transceiver that provides transmission  and  reception  of  AM  signals  in  the  ultra high frequency range of 225.000 to 399.975 MHz for a distance  range  of  approximately  50  miles.    Channel selection is spaced at 0.025 MHz.  A separate receiver is incorporated to provide monitoring capability for the UHF guard frequency (243.0 MHz).  UHF audio output is applied to the audio panel where it is routed to the headsets. NOTE The PRESET channel selector and manual frequency  selectors  are  inoperative  when the     mode     selector     is     set     to     GUARD position.    The  receiver-transmitter  will  be set to the emergency frequency only. Existing capabilities of the HAVE QUICK modified  radio  are  preserved  to  the  maximum  extent possible   when   it   is   operated   in   the   normal   (non- hopping)  mode.    No  new  procedures  are  required  for normal radio operation. To operate in the AM mode, the radio must first be  initialized.    This  initialization  requires the setting of two control entries into the radio, Word of Day (WOD) and Time of Day (TOD).  The WOD defines the choice of  frequency  hopping  pattern  for  the  day.    The  WOD choice  is  a  managerial  function  and  the  same  WOD may be used for one or more  days.  The TOD must be loaded into the clock contained within the radio. The transmitter and receiver sections of the UHF unit operate independently, but share the same power supply and frequency control circuit.  Separate cables route  transmit  and  receive  signals  to  their  respective receiver/transmitter. The    UHF    command    set    is    protected    by    a 5-ampere  UHF  circuit  breaker  in  the  overhead  circuit breaker  panel.    Refer  to  Figure  2-16, Sheets 1 and 2.   The associated blade type antenna is shown in Figure 2-1. b.  Controls  and  Functions.    Refer  to  Figure 3A-3. (1)   Manual Frequency Selector Switch (Hundredths).    Selects  hundredths  digit  of  frequency (2, 3, A or T) in MHz.