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3.3 Position planning
For position planning, please read section 1.3 to
understand and consider every aspect of infrared
distribution.
3.3.1 Rectangular footprints
The determination of the optimal number of infra-red
radiators needed to have complete coverage of a
conference venue can only be done by performing an
on-site test. However, estimation can be done by
‘guaranteed rectangular footprints’, see figure 3.4 and
figure 3.5. The rectangular footprint is smaller than the
actual footprint. Figure 3.5 shows a negative ‘offset’ X
because the radiator is currently mounted beyond the
horizontal point at which the rectangular footprint starts.
Figure 3.4 A typical rectangular footprint for a mounting
angle of 15°
Figure 3.5 A typical rectangular footprint for a mounting
angle of 90°
The guaranteed rectangular footprints of various
numbers of carriers, mounting heights and mounting
angles can be found in section 7.6. The mounting
height is the distance to the radiator from the receiver
reception level and not from the floor. Usually, the
distance from the receiver reception level to the floor is
1 m approximately.
Guaranteed rectangular footprints can also be
calculated with the footprint calculation tool (available
on the documentation CD-ROM). The given values are
for one radiator only, they do not take into
consideration the beneficial effects of overlapping
footprints and reflections (see section 1.3.6).
For up to 4 carriers, experience shows that if the
receiver can pick up the signal from adjacent radiators
(presumed radiators at a distance W, their rectangular
footprints just touching each other seamlessly) the
distance W between these radiators can be increased
by a factor 1.4 approximately (see figure 3.6).
Figure 3.6 The effect of overlapping footprints
3.3.2 Planning radiators
Plan the radiators by following procedure:
1
．
Decide the positioning of the radiators by the
recommendations in section 1.3.
2
．
Decide the applicable rectangular footprints by
consulting the table or calculating with the footprint
calculation tool.
3
．
Draw a picture of the rectangular footprints in the
layout of the room.
4
．
If the receiver can pick up the signals from
neighbored radiators in some areas (according to
fig. 3.6) determine the overlapping effect and draw
the picture of the footprint enlargement in the
layout of the room.
5
．
Check whether there is sufficient coverage with the
radiators at the intended positions.
6
．
If not, add additional radiators.
See figure 1.12 and figure 1.13 for examples of a
radiator layout.
