3.6.1 An Electronic Bearing Line, (EBL), should
be provided with a numeric readout of bearing to obtain within 5 s
the bearing of any object whose echo appears on the display.
3.6.2 The EBL should enable the bearing of a target
whose echo appears at the edge of the display to be measured with
maximum error of not greater than ± 1°.
3.6.3 The EBL should be displayed on the screen
in such a way that it is clearly distinguishable from the heading
indicator. It should not be thicker than the heading indicator.
3.6.4 It should be possible to vary the brilliance
of the EBL. This variation may be separate or combined with the intensity
of other markers. It should be possible to remove the EBL completely
from the screen.
3.6.5 The rotation of the EBL should be possible
in both directions continuously or in steps of not more than 0.2°.
3.6.6 The numeric readout of the bearing of this
EBL should be displayed with at least 4 digits, including one after
the decimal point. The EBL readout should not be used to display any
other data. There should be a positive identification of whether the
bearing indicated is a relative bearing or a true bearing.
3.6.7 A bearing scale around the edge of the display
should be provided. Linear or non-linear bearing scales may be provided.
3.6.8 The bearing scale should have division marks
for at least each 5° with the 5° and 10° divisions clearly
distinguishable from each other. Numbers should clearly identify at
least each 30° division.
3.6.9 It should be possible to measure the bearing
relative to the heading line and relative north.
3.6.10 A minimum of the two independent lines
of parallel index lines should be provided.
3.6.11 It should be possible to move the position
of the EBL origin away from the own ship to any desired point on the
effective display area. By a fast simple operation it should be possible
to move the EBL origin back to own ship's position on the screen.
On the EBL it should be possible to display a variable range marker.