crt superstar900ït manual (11) wm

IGNITION NOISE INTERFERENCE

Use of a mobile receiver at Iow signal levels is nonnally limited by the presence of elcctrical noise. The primary source of noise in automobile installation is from the generator and ignition system in the vchiele. Undcr most operating conditions. w hen signal level is adequate. the baekground noise does not present a serious problem. Also. w hen extrcmely Iow level signals are heing received. the transeeiver may be operated with vehicles engine tunied off. The unit requires verv littlc eurrent and thereforc will not significantly diseluirge the vehicle battery.

Hven though the transeeiver has ANI. and NB eontrols. in sonie installation ignition interferenee may be high enougli to make good communieations impossiblc. The eleetrieal noise may eonie from scvcral sourees. Many possibilitics exist. as \ariations betw cen \ chieles rcquirc different Solutions to reduee the noise.

ANTENNA

A \ ertieally polari/cd. quarter-wavelcngth w hip antenna provides the most reliable operation and greatest rangÄ™. Shortcr. loaded-typc w hip antennas are morÄ™ attraetive. compact and adcquatc for applieations where the maximum possible distanee is not required. Also. loaded whips do not present the problems of high wind resistant imposed by a luli quarter-w a\ elength w hip.

Mobile w hip antennas utilize the metal body of the vchiclc as a ground piane. When mounled at a corner of the vehiele they are slightly direetional. in the direetion of the body of the vehicle. For all practical purpose. however. the radiation pattern is non-direetional. The slight direetional charaeteristie will be obsencd only at extreme distanees. A standard antenna eonneetor (type SO-239) is pro\ ided on the transeeiver foreasy connection to a standard PL-259 eable tennination.

If the transcci\er is not mounted on a metal surlaee. it is neccssary to run a separatc ground w ire from the unit to good metal eleetrieal ground in the Ychiele. When installed in a boat. the transeeiver w ill not operate at maxinmm effieieney w ithout a ground piÄ…te, unlcss the \ essel has a Steel hull

Before installing the transeeiver in a boat. consult your dealer for information regarding an adequate grounding system and prevention of eleetrolysis between fittings in the hull and water.