3-3
3.3 SART (Search and Rescue
Transponder)
A Search and Rescue Transponder
(SART) may be triggered by any X-Band
(3 cm) radar within a range of approxi-
mately 8 nm. Each radar pulse received
causes it to transmit a response which is
swept repetitively across the complete ra-
dar frequency band. When interrogated, it
first sweeps rapidly (0.4
µ
s) throught the
band before beginning a relatively slow
sweep (7.5
µ
s) through the band back to
the starting frequency. This process is re-
peated for a total of twelve complete
cycles. At some point in each sweep, the
SART frequency will match that of the in-
terrogating radar and be within the pass
band of the radar receiver. If the SART is
within range, the freguency match during
each of the 12 slow sweeps will produce a
response on the radar display, thus a line
of 12 dots equally spaced by about 0.64
nautical miles will be shown.
When the range to the SART is reduced
to about 1 nm, the radar display may show
also the 12 responses generated during
the fast sweeps. These additional dot re-
sponses, which also are equally spaced
by 0.64 nm, will be interspersed with the
original line of 12 dots. They will appear
slightly weaker and smaller than the origi-
nal dots.
General procedure for detecting
SART response
1. Use range scale of 6 or 12 nm as the
spacing between the SART responses
is about 0.6nm (1125 m) to distinguish
the SART.
2. Turn off the automatic clutter suppres-
sion.
3. Turn off the Interference Rejector.
4. Turn off the Echo Average.
is a false echo which is caused by the mir-
ror effect of a large object on or close to
your ship as shown in the figure below. If
your ship comes close to a large metal
bridge, for example, such a false echo may
temporarily be seen on the screen.
True
echo
False
echo
Own
ship
Target ship
Mirror image
of target ship
;;
;;
;;
;;
;;
;
;
;
;
;
;
;
;
;
;
;
;;
;;
;
;;
;
;;
;;
;;
;;
;;
;
;
;
;
;;
;;
;
;
;;
;;
;
;;
;
;
;
;
;
;
;
;
;
;;
;;
;
;
;
;
;
;;
;;
;
;;
;;
;
;
;
;
;
;;
;;
;;
;;
;;
;
;;
;;
;
;;
;;
;
;
;
;
;
;
;
;;
;;
;;
;;
;;
;;
;;
;;
;;
;;
;;
Shadow sectors
Funnels, stacks, masts, or derricks in the
path of the antenna block the radar beam.
If the angle subtended at the scanner is
more than a few degrees, a non-detecting
sector may be produced. Within this sec-
tor targets can not be detected.
Radar
antenna
Radar
mast
Blind zone
Содержание FA-2805
Страница 17: ...1 2 1 3 Controls FR 2805 Series Radar Display Unit Overview...
Страница 46: ...1 31 1 32 RADAR 1 and 2 Menu Settings R type...
Страница 47: ...1 32 IMO type radar...
Страница 51: ...1 36...
Страница 52: ...1 37...
Страница 53: ...1 38 Setting for function key 3...
Страница 99: ...A 5 RD1 RD2 IF 2300 INPUT NAV RXDA INPUT NAV RXDB LISTENER 2 mA at 2V...
Страница 108: ...A 14...
Страница 109: ...A 15 Type of acqiusition A M R 2 1 Not used 2 Edition 2 only 1 1...
Страница 110: ...MN 1 MENU TREE...
Страница 111: ...MN 2...
Страница 113: ...MN 4...
Страница 114: ......
Страница 115: ......
Страница 116: ......
Страница 117: ......
Страница 118: ......
Страница 119: ......
Страница 120: ......
Страница 121: ......
Страница 122: ......
Страница 123: ......
Страница 124: ......
Страница 125: ......
Страница 126: ......
Страница 127: ......
Страница 128: ......
Страница 129: ......
Страница 130: ......
Страница 131: ......
Страница 132: ......
Страница 133: ......
Страница 134: ......
Страница 135: ......
Страница 136: ......
Страница 137: ......
Страница 138: ......
Страница 139: ......
Страница 140: ......
Страница 141: ......
Страница 142: ......
Страница 143: ......
Страница 144: ......
Страница 145: ......
Страница 146: ......
Страница 147: ......
Страница 148: ......
Страница 149: ......
Страница 150: ......
Страница 151: ......
Страница 152: ......
Страница 153: ......
Страница 154: ......
Страница 155: ......
Страница 156: ......
Страница 157: ......
Страница 158: ......
Страница 159: ......
Страница 160: ......
Страница 161: ......
Страница 162: ......
Страница 163: ...1 2...
Страница 164: ...2 2...
Страница 165: ......
Страница 166: ......
Страница 167: ......
Страница 168: ......
Страница 169: ......