Galaxy DX 949 Посібник користувача - Сторінка 3
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INSTALLATION
LOCATION
Plan the location of the transceiver and microphone bracket before starting
the installation. Select a location that is convenient for operation and does not
interfere with the driver or passengers. In automobiles, the transceiver is
usually mounted the dash panel with the microphone bracket beside it.
MOUNTING THE RADIO
The transceiver is supplied with a universal mounting bracket. When
mounting the bracket and radio to your car, make sure it is mechanically
strong. Also, provide a good electrical grounding connection to the chassis of
the vehicle. Proceed as follows to mount the transceiver:
1. After you have determined the most convenient location in your vehicle,
hold the transceiver with mounting bracket in the exact location desired.
If nothing will interfere with mounting it in the desired position, remove
the mounting bolts. Before drilling the holes, make sure nothing will
interfere with the installation of the mounting bolts.
2. Connect the antenna cable plug to the standard receptacle on the rear
panel. Most transceiver antennas are terminated with a type PL-259 plug
and mate with the ANT receptacle.
3. Connect the red DC power input wire (with the fuse) to +13.8V DC.
This wire extends from the rear panel. In automobile installation, +13.8V
DC is usually obtained from the accessory contact on the ignition switch.
This prevent the set being left on accidentally when the driver leaves the
car and also permits operating the unit without the engine running.
Locate the accessory contact on most ignition switches by tracing the
power wire from the AM broadcast receiver in the car.
4. Connect the black lead to –13.8V DC. This is usually the chassis of the
car. Any convenient location with good electrical contact (remove paint)
may be used.
5. Mount the microphone bracket on the right side of the transceiver or
near the transceiver, using two screws supplied. When mounting in an
automobile, place the bracket under the dash so that microphone is
readily accessible.
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IGNITION NOISE INTERFERENCE
Use of a mobile receiver at low signal levels is normally limited by the
presence of electrical noise. The primary source of noise in automobile
installation is from the generator and ignition system in the vehicle. Under
most operating conditions, when signal level is adequate, the background
noise does not present a serious problem. Also, when extremely low level
signals are being received, the transceiver may be operated with vehicle
engine turned off. The unit requires very little current and therefore will not
significantly discharge the vehicle battery.
Even though the transceiver has ANL and NB controls, in some
installations ignition interference may be high enough to make good
communications impossible. The electrical noise may come from several
sources. Many possibilities exist as variations between vehicles require
different solutions to reduce the noise.
ANTENNA
A vertically polarized, quarter-wavelength whip antenna provides the most
reliable operation and greatest range. Shorter, loaded-type whip antennas are
more attractive, compact and adequate for applications where the maximum
possible distance is not required. Also, loaded whips do not present the
problems of height imposed by a full quarter-wavelength whip.
Mobile whip antennas utilize the metal body of the vehicle as a ground
plane. When mounted at a corner of the vehicle they are slightly directional,
in the direction of the body of the vehicle. For all practical purpose, however,
the radiation pattern is nondirectional. The slight directional characteristic
will be observed only at extreme distances. A standard antenna connector
(type SO-239) is provided on the transceiver for easy connection to a
standard PL-259 cable termination.
If the transceiver is not mounted on a metal surface, it is necessary to run a
separate ground wire from the unit to good metal electrical ground in the
vehicle. When installed in a boat, the transceiver will not operate at
maximum efficiency without a ground plate, unless the vessel has a steel
hull.
Before installing the transceiver in a boat, consult your dealer for
information regarding an adequate grounding system and prevention of
electrolysis between fittings in the hull and water.
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