(1) SINCGARS is replacing all AN/PRC-77 manpack and AN/PRC-12 series vehicular-
mounted VHF and airborne VHF frequency modulation (FM) radios. SINCGARS accepts either digital
or analog inputs and imposes the signal onto a frequency hopping (FH) output signal. In FH, the input
changes frequency about 100 times per second over portions of the tactical VHF range (30 MHz to 88
MHz). This hinders enemy interception and jamming units from locating or disrupting friendly
(2) SINCGARS radio systems are modular component sets. The receiver-transmitter (RT) is
the primary component. The two ground-unit versions are the RT-1523 and RT-1439. The RT-1523,
which has internal communications security (COMSEC) circuits, is an integrated COMSEC (ICOM)
radio. The non-ICOM RT-1439 uses the VINSON secure device. The secure devices are compatible,
provided the same cryptonet variable is used in the ICOM radio and the VINSON device. The avionic
versions (RT-1476/77/78) require external COMSEC devices. Airborne and ground versions are
interoperable in FH and single-channel versions. SINCGARS is compatible with all current United
States (US) and allied VHF radios in the single-channel mode with channels at intervals of 25 kHz. It
stores eight single-channel frequencies and six separate hopsets. In addition, the cue and manual
frequencies are included in the eight single-channel frequencies.
(3) SINCGARS directly accepts either analog (VOICE or FREQUENCY shift key) or digital
input signals. SINCGARS processes the incoming signal into a digital data stream operating at 16,000
bits per second (bp/s). Digital data input at that speed can be input directly. The radio is equipped with
a data rate adapter, which permits a slower rate to be used when needed. The slower speed is desirable
since the radio provides error correction for speeds from 75 bp/s to 4800 bp/s.
(4) An advantage of SINCGARS over previous radios is its ability to control output power.
The RT has three power settings that vary transmission range from 300 meters to 8 kilometers (900 feet
to 5 miles). Adding a power amplifier (modular component) increases its range to 35 kilometers (22
miles) or line-of-sight (LOS). The variable output power level allows users to lessen the signature given
off by the radio set. The ability to use lower power is particularly important at major command posts
(CP) that operate in multiple networks.
(5) The two main categories of ancillary equipment associated with SINCGARS are remote
control devices and data fill/variable storage transfer devices. Other devices that generate signals passed
over SINCGARS radios, such as data terminals, are classified as input/output devices.
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