Iveco DAILY M.Y. 2012, Инструкция для тренажера

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5-30
SPECIAL INSTRUCTIONS FOR ELECTRONIC SUBSYSTEMS D
AILY
Base - 02/2012 Printed 603.95.241
Electrical system: modifications and drawing-off power
c) The coaxial antenna cable must be positioned taking care to:
- use a low loss, top quality product, with the same impedance as the transmitter and the antenna (see Figure 5.24);
- in order to avoid interference and malfunctioning, create a path that maintains an adequate distance (min. 50 mm) from
pre-existing cabling or from other cables (radio, amplifiers and other electronic equipment), fixed keeping the minimum
distance from the metal structure of the cab and using existing holes in the sheet metal;
- do not shorten or lengthen; avoid unnecessary tangles, tension, folds and crushing.
d) Outside the cab, the antenna must be installed on the vehicle on a metal base with a wide surface if possible; otherwise it must
be fitted as vertically as possible, with the connecting cable pointing downwards and therefore following the Manufacturer’s
fitting instructions and warnings (see Figure 5.23).
Installation on the centre of the roof is to be considered the best by far, as the grounding surface is proportional in all directions,
while fitting on a side or any other part of the vehicle makes the grounding area proportional to the grounding of that part.
Inside the cab, the transmitter equipment must be positioned as shown in Diagram 5.25.
e) The quality of the antenna, the mounting position and a perfect connection to the vehicle structure (ground) are factors of
fundamental importance to guarantee the best performance of the transmitter equipment.
Some specific instructions are given below for each type of equipment
Amateur equipment for CB (27 MHz) and 2m band (144 MHz)
The transmitter part must be installed in a separate area from the vehicle’s electronic components.
•
The SWR ratio (Standing Wave Ratio) must be as close as possible to the unit (1.5 is recommended) while the maximum must
not be greater than 2.
•
The ANTENNA GAIN values must be as high as possible and guarantee a sufficient level of spatial uniformity, characterised by
deviations in relation to the average value of the order of 1.5 dB in the typical CB band (26.965-27.405 MHz).
•
The value of the RADIATED FIELD in the cab must be as low as possible, and therefore < 1 V/m.
The limits imposed by the current European Directive must not be exceeded in any case.
To determine whether the system is functioning well and to check that the antenna is calibrated, it is suggested that the following
information is taken into account:
1) if the SWR is higher on the lower channels than on the higher ones, the antenna should be lengthened
2) if the SWR is higher on the higher channels than on the lower ones, the antenna should be shortened
After having calibrated the antenna, it is advisable to re-check the SWR value on all the channels.