Galaxy DX−33HML Instrukcja obsługi - Strona 6

Przeglądaj online lub pobierz pdf Instrukcja obsługi dla Transceiver Galaxy DX−33HML. Galaxy DX−33HML 8 stron. Full channel am/fm mobile transceiver

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 installations

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 same installations

ignition interference may be high enough to make good communications

impossible. The electrical noise may come from several sources. Many possibilities

exist and 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, the 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 distance. A standard antenna connector (type SO239) 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 a 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.

- 5 -

17. POWER. Accepts 13.8V DC power cable with built-in fuse (4 amp.) to be

connected.

18. EXT SP. Accepts 4 to 8 ohms, 5 watt external speaker to be connected. When

external speaker is connected to this jack, the built-in speaker is automatically

disconnected.

19. PA. SP. Used to connect a PA speaker (8 ohm 4W) for PA operation. Before

operating PA you must first connect a PA speaker to this jack.

20. ANTENNA. Accepts 50 ohm coaxial cable with a type PL-259 plug to be

connected.

21. F.C. This socket is optional for the accessories FREQUENCY COUNTER

model FC-347, to indicate the value of the frequency ranges used.

- 10 -