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Match words with their meanings.
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| Timer | — | equipment which is capable of determining by radio echoes the presence of object, their direction and range. |
| Radar | — | the synchronizer of the whole system. |
| Transmitter | — | a device which takes ultra-high frequency radio wave energy from the transmitter and radiates it in a beam. |
| Antenna | — | a device which transmit the energy. |
| Receiver | — | a device which picks up the returning echo through its antenna and translates it into visual readable signals on a fluorescent screen. |
6. Translate the following additional text without a dictionary:
Radar Guides Harbour Traffic
Radar is an electronic device which gives ranges of an object by timing the interval between the transmission and reception of reflected impulses. Owing to the directive quality of the beam of the impulses, bearings may also be measured.
A number of world's largest ports have already installed radar systems in their harbours. Radars guide* ship traffic in fog and bad weather. They not only help ships to enter and leave the harbour during poor visibility, but also provide continuous observation of shipping and give immediate information on the location of ships in the harbour.
From a radio control room*** having the necessary transmitting equipment of ship-to-shore communication, with a radar unit**** set at a certain distance, the operator can observe the harbour and give necessary orders immediately to ships. It is very important for preventing ships' collisions at sea.
Notes:
*to guide - направлять, управлять
**traffic - движение кораблей
***a radio control room - радиорубка
**** a radar unit - РЛС
LESSON 4. LORAN
1.Read the following words:
suitable - unsuitable accurate- inaccurate
desirable - undesirable different - indifferent
available - unavailable possible - impossible
extended - unextended decisive - indecisive
foci receipt perpendicular
simultaneous simultaneously instead
cathode-tube hyperbola ionosphere
Grammar.
1) Сложноподчиненные предложения c придаточным условием.
Союзы: if, unless, in case
2) Различные значения глагола «would».
1) If he is free, he usually comes to see us.
1-й тип If he is free, he will come to see us in summer.
2-й тип If he were free, he would come to see us.
3-й тип If he had been free, he would come to see us, but he had been busy. We shall put to sea unless it rains (in case it does not rain).
2) He said he would come in time.
If they were there, they would help us.
In his childhood he would often go to the port to watch ships.
Visit your friends on Sunday, they would be pleased to see you.
3. Read the following text:
LORAN
(Long Range Navigation)
Loran means Long Range Navigation. It is a cathode-tube electronic navigation aid which measures the time interval between the receptions of synchronized signals from two stations.
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A ship at C on the perpendicular bisector of AB would receive both signals at the same time if they were sent simultaneously. In like manner, a ship at С' would also receive the two signals at the same time. A ship at D would receive signal A before signal B. The difference in time of receipt at D would be repeated at D'. In fact, a ship anywhere along a hyperbola would have the same time difference as any other ship on the same hyperbola. A number of such hyperbolas could be drawn with foci at A and B. Each curve would have its own unique time difference, if the signals, instead of being simultaneous (two symmetrical curves per time difference), were properly phased in time.
A ship obtains a line of position, therefore, from the signals of two stations. If a fix is desired, at least a second line of position must be obtained from two other loran stations, a celestial sight, or other means. The loran waves are received by ground wave or by one or more reflections (or refractions) from ionosphere layers. Ground waves are more accurate but are absorbed more quickly than sky waves. The ship does not transmit when using loran navigation. The service is available 24 hours in the day in any weather, and coverage extends from the USA to Europe, Alaska, and the Far East. But there still remain many parts of the seven seas that are not covered by loran. The system is unsuitable near the base line extended because it is inaccurate.
The range of any two stations is about 700 miles by day and 1400 by night.
Notes:
* Long Range Navigation — радионавигационная система дальнего действия /Лоран/
**Слово 'hyperbola' - существительное романского происхождения; оно имеет две формы множественного числа - hyperbolae — по законам латинского языка и hyperbolas - по законам английского языка.
***foci - множественное число от существительного 'focus' - фокус, центр.
4. Words to be learnt:
reception — прием /сигналов/
receipt — принимать
curve — кривой
ionosphere — ионосфера
simultaneous — одновременный
available — доступный, имеющийся в распоряжении
to extend — простираться
EXERCISES
1. What's the Russian for:
reception, curve, ground, sky, wave, difference, long-range navigation, perpendicular, simultaneous, to send waves, to extend, to cover, to reflect, to obtain, service.
2. Translate into Russian:
1. A ship at С on the perpendicular bisector of AB would receive both signals at the same time if they were sent simultaneously.
2. Each curve would have its own unique time difference, if the signals were properly phased in time.
3. If a fix is desired, a second line of position must be obtained from the two other loran stations, a celestial sight or other means.
3. Translate into English:
Радионавигационная система «Декка»
Ее основные технические данные:
Диапазон рабочих частот - 80-150 кГц
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Мощность излучения - 2 кВт
Вид колебаний – незатухающие
Длина базовой линии пары станций - около 100 миль
Дальность действия:
днем — до 1000 миль, ночью — до 300 миль
Точность определения линии положения:
днем - от 10 до 450 м, ночью - от 20 до 450 м
4. Answer the following questions:
1) What is Loran?
2) Can a ship obtain a line of position from the signals of two stations?
3) What parts of the world are covered by Loran?
4) Is the service available 24 hours in the day in any weather?
5) What is the range of any two stations by day and by night?
5. Translate the following text without a dictionary:
Radio navigation aids include radio position fixing systems - Gee, Standard Loran, Decca Navigator and also radar. (The latter may consist of a radar set carried in a ship or of a set mounted ashore).
Gee is a system of radio position finding which is used by ships and aircraft simultaneously. Three ground stations situated about 70 miles apart are employed to obtain a fix; two stations are necessary for a position line. These ground stations radiate pulses, which are received in the craft and displayed on a cathode-ray indicator. The time interval between the arrival of a pulse from each of the central (master)* station and a pulse from each of the slave** station is measured on this indicator. The position lines given by each pair of stations are Hyperbolas with the station as foci. The system operates in the band 20-85 Mc/sec.
The ground stations radiate pulses of 5 micro-seconds duration rising in 3/4 micro-seconds with a peak amplitude of 300 kw. Master stations radiate 500 pulses per second and slaves 250 per second.
Notes:
*central (master) station - главная или задающая станция slave
**station - ведомая или синхронизированная станция
LESSON 5. OMEGA SYSTEM
1. Read the following words:
assign Argentina Haiku Minnesota
kilohertz Australia Hawaii New Zealand
kilocycle Bratland Japan Norway
relaible La Reunion Chile Port of Spain
strategic Forestport Trinidad Madagascar
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