RADAR CONFIGURATION
3.18 Rev. E
3.9.1 Trigger Delay
Press the A button of fig. 3.9.1 to adjust the Trigger Delay. The Trigger delay is caused by
the path length mismatch for the trigger and video signal.
The video path delay is much longer because it's the result of the transmission trough the
waveguide to the antenna and backwards.
The delay depends from the length and type of waveguide used in the installation.
The range scale is automatically set to 0.25 NM. Press the arrow buttons in order to
enlarge or squeeze the picture and adjust the delay between video and trigger from 0
meters to a maximum of 384 meters.
The delay adjustment is visible in real time on the PPI around the ship.
The picture on the right shows two different samples of wrongly adjusted trigger delay:
• in the n.1 it is clear that the dock, or the pier is
attracted to the centre, the video is too squeezed, so
the delay value is too high;
• in the n.2 the dock, or the pier is made farer from the centre, the video is too
enlarged, so the delay value is too low.
NOTE
For SRT transceivers it also possible to change the delay to negative
numbers. In this case the trigger from the TXRX will be anticipated in time
in respect to the video. This negative setting is needed when trigger and
video are passing trough long coaxial cables with different propagation
times, the video cable being the slowest one.
That usually happens for all installations with an SRT Adapter Box as
buffer amplifier and cable lengths more than 150 meters.
NOTE
If the Alpha Expansion PCB is installed, on channel 1 and 2, two optional
buttons C for Trigger and Video polarity will be available.
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