TM 1-1510-223-10 Change 3          3-15 NOTE Always key the microphone after selecting a new frequency to initiate antenna tuning. Otherwise poor reception or failure to hear a ground station which is calling you may be experienced. Before keying the microphone to talk, you should depress  the  store  (STO)  switch  momentarily. This will allow you to listen on the transmit fre- quency  to  see  if  another  aircraft  is  calling  the same ground station. Some Canadian public correspondence stations require the reception of a 1,000 Hz signal from an aircraft calling the station before it will answer. This signal may be sent by keying the radio and then simultaneously depressing the store (STO) switch. 3-12.   VHF-FM    TRANSCEIVER    (AN/ARC-201A(V), SINCGARS. a.   Description.  The single channel ground and air- borne radio system (SINCGARS, AN/ARC-201(V)) pro- vides  VHF-FM  radio  communications.  The  frequency range  is  30  to  87.975  MHz.  The  system  provides  for secure communications through interfacing with a voice security system. The system is protected by a 10-ampere circuit breaker placarded FM, located on the overhead circuit breaker panel (fig. 2-7). Control of the VHF-FM transceiver is provided by the aircraft survivability equipment/avionics control system (ASE/ACS). b.   Normal Operation. NOTE Some operations in the VHF-FM transceiver re- quire   several   seconds   to   accomplish.   While these operations are active, the TUNING legend (multifunction display, fig. 4-2), will be displayed and  some  bezel  buttons  will  become  inactive until tuning is complete. (1)    Turn-on Procedure. 1.   BATTERY switch (overhead control panel, fig. 2-13) - ON. 2.   AVIONICS MASTER POWER switch (over- head control panel, fig. 2-13) - ON 3.   Transmitter-intercom selector switch (audio control panel, fig. 3-1) - 2. 4.   FM/AM  alternate  communication  selector switch (pedestal extension, fig. 2-12) - As required. 5.   D mode selector switch (multifunction dis- play,  fig.  4-2)  -  Depress  to  select  COMM control page. NOTE On power-up, the transceiver is put into the self- test mode for approximately 30 seconds. During this period, the legend TUNING is displayed ad- jacent to L1 on the COMM control page and at the top center of this page and the transceiver will not respond to operator inputs. (2)    COMM  control  page.    The  COMM  control page shows the status of the VHF-FM and has a frequen- cy list. Radio name, mode of operation, selected channel and frequency (or hopset number/AJ NET number), and plain/cipher indications are presented. Two arrows indi- cate which transceiver each pilot has selected with the transmitter-intercom selector switch (audio control pan- el, fig. 3-1). NOT INST - The aircraft is configured for the equip- ment but it is not installed. FAIL - The equipment has failed. Blank - No legend at the bezel switch indicates that the aircraft is not configured for the equipment. NOTE The following definitions apply to the legend ad- jacent to the bezel switches: If  L1  line  selection  switch  is  depressed  with  the scratchpad empty: The FM frequency list will be displayed in the box in the center of the multifunction display (MFD). The HOPSET/LOCKSET list will be displayed in the box in the center of the MFD if the frequency hopping mode is active. The legend at R4 will change to FM FREQ. The legend at R5 will change to 2-FM SETUP. If  the  VHF-FM  transceiver  is  in  the  single  channel mode and valid data is scratchpadded, depressing L1 will cause the transceiver to be returned and the display at L1 to be updated to reflect the scratchpadded data. Valid data is: A channel (1 through 20, or C or E). A frequency (30,000 to 87.975 with leading and trail- ing zeroes and decimal points optional).