User's Manual

NACOS Platinum
ED 3100 G 110 / 02 (2011-10)
Operating Instructions
A-1 General Information
A RADAR.fm / 10.11.11
A-12
Short Pulse/Long Pulse is available for any range of the radar. The internal pulse length changes with
respect to the selected range automatically. For detailed information on the pulse lengths for any range,
please refer to the table in section 1.4.2 of the Operating Instructions.
The default setting for the pulse length should be Short Pulse. A longer pulse has a higher energy, but
not a higher amplitude. Thus, it delivers stronger echoes. It is allowed to switch between the two pulse
lengths at any time.
If target enhancement or any other filtering methods are active, the stronger echoes are processed by
the filters and are able to improve a weak radar picture.
The Tune function can be set manually or automatically. Tune influences the center frequency of the
entire radar echo evaluation process. For the adaption of Tune, no radar echoes are needed and inter-
ference from other radar devices is suppressed so that automatic tuning (AFC) has the best results and
should be used as default. An optimum tuning is not only important for a clear visual display of the
targets on the video but is also a necessary prerequisite for the ARPA functions.
Gain setting influences the amplitudes of all echoes and works like an amplifier that makes it possible
to enhance all echoes and noise in the same way in order to get a better picture. But, as said before,
also the noise will be amplified and can disturb the clear display of targets. Gain should in any case be
set in such a way that slight noise is always visible.
Rain can be set to Off or Low, Medium and High. With an optimal setting of Rain only the boundary
of the rainy area facing towards the transceiver is displayed and echoes within or behind the rainy area
will be displayed if their echo is still strong enough after having been filtered. Weak echoes will not be
displayed if their echo is too small after the signal has been processed by the filter.
For each setting, a correlative signal processing takes place and filters out the noise of the rainfall.
Echoes which are strong enough will be displayed, others may disappear.
Sea can be set to manual or automatic mode. In manual mode, its setting influences the amplitudes of
the radar echoes in such a way that it attenuates echoes close to the antenna very much and that it
attenuates echoes which are more distant to it only very little. Due to the fact that the distance of a
target is represented by the time its echo needs to return to the antenna, this is called „sensitivity-time-
control“ (STC). Nevertheless, echoes which are as strong as the unwanted reflections of the sea may be
suppressed and not visible, or they may appear and disappear, depending on how strong the
surrounding unwanted reflections are.
In automatic mode, a fixed, approved value for the Sea filter is set. Advantages or limitations to the
effect are the same as in manual mode.
In the case of heavy rain, snow and hail, it can be expected that, even if the setting is
correct, radar targets which only produce weak reflections - especially targets situated
behind a strong rain front - will remain undetected. Such targets can appear suddenly
when leaving the rainy area.