2017航海英语复习三Key word 10: Radar and ARPA（60）A335. Radar makes it possible and much safer for us to sail __.A. in dense fogB. in boisterous weatherC. in the open seaD. in rivers【知识点】雷达的使用【解析】主要作用：雾航B380. Radar makes the most accurate determination of the __.A. direction of a targetB. distance to a targetC. size of a targetD. shape of a target【知识点】雷达的使用【解析】雷达测距最准确。
相关题目A382. Without doubt the radar is a highly important navigation aid. But duty officer shall aware that __when using it.A. Its range reading is more accurate than its bearing readingB. A low-lying coastline with a long, flat beach will show up properly on the radar.C. Radar is only aimed at collision avoidance.D. the use of radar is necessary only when visibility is restricted、D527. Radar is not only to obtain ______, but also to measure their distance away from you.A. brightness of objectsB. color of targetsC. shape of targetsD. bearing of objectsD361. Which statement concerning the operation of radar in fog is TUREA. radar ranges are less accurate in fogB. navigation buoys will always show up on radarC. a sandy beach will show up clearer on radar than a rocky cliffD. small wooden boats may not show up on radarB327. The correct method of switching off a marine radar is to turn power switch to ____ position first, then to ______ position.A. off / standbyB. standby / offC. standby / closeD. close / standby【知识点】雷达的使用【解析】雷达关机步骤。
B606、As the radar antenna scans through ____ a rotation , it can be show where the target is relative to your position .A. 60 degreeB. 360 degreeC. 180 degreeD. 90 degree【知识点】雷达的使用【解析】雷达天线。
A345. The radar control that reduces weak echoes out to a limited distance from the ship is the __A. sensitivity time control ( sea-clutter control)B. receiver gain controlC. brilliance controlD. fast time constant ( differentiator )【知识点】雷达的使用（控钮）【解析】近距离的杂波相关题目D346. The radar control that shortens all echoes on the display and reduces clutter caused by rain or snow is the ______.A. sensitivity time control (sea clutter control)B. receiver gain controlC. brilliance controlD. fast time constant (differentiator)D372. ______is on the panel of radar.INVERTERA391. What is the purpose of VRM controlA. To measure distance accuratelyB. To measure bearing accuratelyC. To measure range and bearingD. To adjust radar monitor【知识点】雷达的使用【解析】活动距标圈。
D557. SWEEP INT on radar panel is the abbreviation of______．A．sweep introduction B．sweep interest C．sweep intention D．sweep intensity 【知识点】雷达的使用【解析】扫描亮度A605、When will you have to adjust gainA. every time you change rangesB. each watchC. every dayD. every week【知识点】雷达的使用【解析】增益：每次改变量程后需重新调整。
D352. When hitting a solid object such as a ship or an airplane, the radar waves are reflected back ______ they came.A. in the wayB. the wayC. by the wayD. through the path【知识点】雷达的工作原理【解析】雷达波路径B360. Which general statement concerning radar is FALSEA. raising the antenna height increases the radar rangeB. the ability of radar to detect objects is unaffected by weather conditionsC. radar bearing are less accurate than radar rangeD. radar should be checked regularly during clear weather to ensure that it is operatingproperly【知识点】雷达的工作原理【解析】雷达探测物标的能力会受到天气的影响。
A348. The radio waves used for radar are very short，only ______ long．A．a few centimeters B．a few fathoms C．a few meters D．a few feet【知识点】雷达技术指标（波长）【解析】航海雷达主要是3cm和10cmC336. The 10-cm radar as compared to a 3-cm radar of similar specifications will ______.A. be more suitable for river and harbor navigationB. provide better range performance on low lying targets during good weather and calm seasC. have a wider horizontal beam widthD. have more sea return during rough sea conditions【知识点】雷达技术指标（波长）【解析】1）最大作用距离：正常天气下，3cm雷达的大；雨雪天，10cm雷达的大。
2）距离分辨力和测距精度：波长短，脉冲前沿短，脉冲宽度短——3cm好。
3）方位分辨力和测方位精度：波长越短，波束宽度越窄——3cm好。
4）抗杂波能力：10cm好。
相关题目D337. The 3-cm radar as compared to a 10-cm radar with similar specifications will ______.A. give better range performance in rain, hail, etc.B. display small targets in a mass of dense sea clutter at a greater rangeC. have less sea return in choppy rough seasD. display a more maplike presentation for inshore navigationA364. Coral atolls, or a chain of islands at right angles to the radar beam, may show as a long line rather than as individual targets due to ______.A. the effects of beam widthB. limitations on range resolutionC. the pulse length of the radarD. the multiple-target resolution factor【知识点】雷达技术指标（天线波束宽度）【解析】天线水平波束宽度对方位分辨力的影响。