Sart (Search And Rescue Transponder); Sart Description - Furuno 1835 Operator's Manual

2. DESCRIPTION OF RADAR
2.3

SART (Search and Rescue Transponder)

2.3.1

SART description

When any X-band radar reaches within a range of approximately 8 nm, a Search and
Rescue Transponder (SART) sends a response to the radar signal. The transmitter
signal of response is 12-sweeps signal between 9,500 MHz to 9,200 MHz. The time
of slow sweep signal is 7.5 μs and the time of fast sweep signal is 0.4 μs. When the
radar receives this SART signal, a line of 12 dots appears. When the position of SART
is distant, the radar display shows only slow sweep signals like the illustration of
screen A.
When the radar reaches the SART within approximately 1 nm, the radar display can
also show the 12 responses of fast sweep signals like the illustration of screen B. The
position of the SART is the closest position of the radar echoes.
Screen A: When SART is distant
Echo from SART
Position of
SART
2-6
Radar antenna
beamwidth
24 NM
Your ship
position
9500 MHz
9200 MHz
7.5 μs
Low speed sweep signal
Sweep start
High speed sweep signal
SART echo
Screen B: When SART is close
Lines of 12 dots are displayed in
concentric arcs.
1.5 NM
SART mark
length
Radar receiver
bandwidth
Sweep time
95 μs
Echo from
SART
Your ship
position
Position of
SART