Racon (Radar Beacon) - Furuno MODEL 1622 Operator's Manual

Any radar bandwidth of less than 5 MHz will
attenuate the SART signal slightly, so it is
preferable to use a medium bandwidth to ensure
optimum detection of the SART.
Radar side lobes
As the SART is approached, sidelobes from the
radar antenna may show the SART responses
as a series of arcs or concentric rings. These
can be removed by the use of the anti-clutter
sea control although it may be operationally
useful to observe the sidelobes as they may be
easier to detect in clutter conditions and also
they will confirm that the SART is near to the
ship.
Gain
For maximum range SART detection the normal
gain setting for long range detection should be
used, that is, with background noise speckle
visible.
STC control
For optimum range SART detection, this control
should be set to the minimum. Care should be
exercised as wanted target in sea clutter may be
obscured. Note also that in clutter conditions the
first few dots of the SART response may not be
detectable, irrespective of the setting of the
anti-clutter sea control. In this case, the position
of the SART may be estimated by measuring
9.5 nm miles from the furthest dot back towards
own ship.
Some sets have automatic/manual anti-clutter
sea control facilities in which case the operator
should switch to manual.
FTC control
This should be used normally (to break up areas
of rain) when trying to detect a SART response
which, being a series of dots, is not affected by
the action of the anti-clutter rain circuitry. Note
that Racon responses, which are often in the
form of a long flash, will be affected by the use
of this control.
Some sets have automatic/manual anti-clutter
rain control facilities in which case the operator
should switch to manual.

2.4 Racon (Radar Beacon)

A racon is a radar transponder which emits a
characteristic signal when triggered by a ship's
radar (usually only the 3 centimeter band). The
signal may be emitted on the same frequency
as that of the triggering radar, in which case it is
superimposed on the ship's radar display
automatically.
The racon signal appears on the PPI as a radial
line originating at a point just beyond the
position of the radar beacon or as a Morse code
signal (figure below) displayed radially from just
beyond the beacon.
Figure 2-7 Appearance of Racon signal
on the radar display
Racon
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