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Sum up what the text said about the wireless telegraphy.
LESSON 2. RADIO DIRECTION FINDERS
1. Read the new words:
radio direction finder радиопеленгатор
the Allies Антанта; Тройственный союз ( Англия, Франция и Россия )
to track следить, прослеживать; выслеживать
U-boat немецкая подводная лодка
to sense опознавать; воспринимать, измерять; контролировать
radiogoniometer радиопеленгатор
loop aerial рамочная антенна
to wire соединять [монтировать] проволокой
field coil катушка возбуждения; обмотка возбуждения
search coil измерительная катушка
to rotate вращать(ся)
to resonate резонировать
aerial circuit антенный контур , воздушная линия ( электропередачи )
to diminish уменьшать(ся), сокращать(ся)
magnetic flux магнитный поток, поток магнитной индукции
automatic direction finder автоматический радиопеленгатор
solenoid соленоид
to spin крутить(ся), вертеть(ся)
peak высшая точка, максимум , пик
trough самая глубокая точка, низшая точка
compass rose девиационный круг компаса
а string ряд, цепочка
VOR ( very-high-frequency omnidirectional range) всенаправленный курсовой радиомаяк УKB-диапазона
GPS (Global Positioning System) глобальная система навигации и определения положения
user-friendly ориентированный на пользователя, удобный для пользователя
2. Read the text and translate it:
Due to radio's ability to travel very long distances "over the horizon", it makes a particularly good navigation system for ships and aircraft that might be flying at long distances from land.
High frequency radio direction finders (known as HF/DF or huff-duff) were employed by the Allies to track German U-boats during WWII.
The earliest radio direction finder was the radiogoniometer invented by Bellini and Tosi in 1907. In the BT radiogoniometer, two loop aerials (one positioned North-South and the other East-West, or Fore-Aft and Port-Starboard on a boat) were each wired to a field coil (which were mounted at right angles to each other). A rotating ‘search coil’ (which was attached to the receiver) was then placed between the two field coils. A loop aerial resonates best when the radio wave approaches it from the side, and so the degree to which an electric current is induced in the aerial circuit diminishes as the wave’s angle of approach increases. Each field coil will then produce a magnetic field proportional to the current induced in the aerial. The search coil receives a proportion of the magnetic flux from each field coil depending on the direction it faces. The search coil achieves maximum magnetic flux when it favors the coil with the greater magnetic field, and it is at this position that the search coil points in the direction of the radio transmission.
In more recent times the task of finding the signal has been automated in the automatic direction finder, or ADF. In this system the antenna consists of a small cylinder of wire, a solenoid that is highly directional, which is spun by a motor. The electronics listen either for the repeated "peak" in the signal, or just as commonly, the "trough" when the signal drops to zero when the antenna is at right angles to the signal. A small lamp attached to a disk is timed to spin at the same speed as the antenna, so when the peak or trough is detected the lamp flashes briefly. To the human eye it appears to be a single spot of light on top of a compass rose.
RDF was once the primary form of aircraft navigation, and strings of beacons were used to form "airways" from airport to airport. In the 1950s these systems were generally being replaced by the VHF omni range (VOR) system, in which the angle to the beacon can be measured from the signal itself, with no moving parts.
Today all such systems are being generally removed in favour of the much more accurate and user-friendly GPS system. However the low cost of ADF systems today has meant something of a comeback, whereas the expensive VOR systems will likely all be switched off before 2010.
3. Answer the following questions:
1) What are the radio direction finders used for?
2) Who was the inventor of the earliest radio direction finder?
3) What elements did the radiogoniometer consist of?
4) How did the radiogoniometer work?
5) What is ADF?
6) Why did GPS system remove ADF and VOR systems?
4. Give the equivalents, using the text:
a) путешествовать на далекие расстояния, навигационная система, направление передачи, нос, корма, левый борт , правый борт, вращающаяся измерительная катушка, прикреплять к приемнику, электрический ток уменьшается, создавать магнитное поле, зависеть от направления, максимальный магнитный поток, сигнал понижается до нуля, человеческий глаз, воздушная навигация, заменить систему, более точный и удобный для пользователя.
b) to travel very long distances, navigation system for ships and aircraft, two loop aerials, to be wired to a field coil, rotating ‘search coil’, electric current is induced, to produce a magnetic field, a proportion of the magnetic flux, direction of the radio transmission, signal drops to zero, to spin at the same speed as the antenna, the lamp flashes briefly, a single spot of light, more accurate and user-friendly GPS system.
5. Put the questions to the underlined words:
1) High frequency radio direction finders are known as HF/DF or huff-duff.
2) The earliest radio direction finder was the radiogoniometer.
3) Two loop aerials were each wired to a field coil.
4) The degree to which an electric current is induced in the aerial circuit diminishes.
5) The search coil receives a proportion of the magnetic flux from each field coil.
6) In the ADF system the antenna consists of a small cylinder of wire.
6. Translate from English into Russian, paying special attention to the “Complex Subject” Construction:
1) Radio direction finders are assumed to be good navigation devices for ships and aircraft.
2) RDF was known as a primary form of aircraft navigation.
3) RDF system is likely to be widely used in the 1930’s and 1940’s.
4) In WWII, ship-based huff-duff was found to be implemented with a number of changes to the original BT radiogoniometer design.
5) True direction was found either by incorporating an antenna into the huff-duff unit.
6) Wires from each dipole seem to be looped together into a single field coil.
7) For a long time the general concept of the original radiogoniometer was thought to be unchangeable.
8) The above mentioned text is certain to be very interesting.
7. Translate from Russian into English:
1) Любой прибор, излучающий электромагнитные волны, можно не только легко
обнаружить, но и зафиксировать его координаты.
2) Во времена ВМВ радиопеленгация служила для выявления местоположения вражеских радиомаяков.
3) Радиопеленгатор представляет собой систему, состоящую из радиопередатчика и антенны.
4) Радиопеленгаторы применялись для отслеживания немецких подводных лодок.
5) Первый радиопеленгатор был изобретен в 1907 году.
6) Две рамочные антенны прикреплялись к катушке возбуждения.
7) На сегодняшний день система GPS связи является наиболее точной и удобной для пользователей, поэтому она вытесняет своих предшественников.
8.Sum up the information about radio direction finders.
LESSON 3. RADIO BEACONS
1. Read the new words:
radio beacon радиомаяк
aid помощь
overcast сплошная облачность, облачный, пасмурный
to distract отвлекать
urban sprawl неконтролируемая застройка прилегающих к городу территорий
handicap помеха, препятствие
to hasten ускорять ( какой-л. процесс и т. п.)
to space располагать с промежутками
Morse-code signal сигнал кода Морзе
beam луч света, луч
to merge сливать(ся), соединять(ся)
steadyравномерный, ровный
drift смещение, отклонение | отклоняться
to strayсбиться с пути, отклониться
ILS ( instrument landing system) система посадки по приборам
compass locator радиостанция приводная
to orient ориентировать, выравнивать, определять местонахождение
glideslope глиссада , наклон (склонение) глиссады
to guide вести, регулировать, направлять курс
homing beacon приводной радиомаяк
homing aids средства самонаведения
VFR ( visual flight rules) правила визуального полёта
voice circuit цепь передачи речевых сигналов
preflight предполётный
homing signal сигнал самонаведения
obsoleteустарелый
backupвспомогательные средства, резервное устройство
artefact (любой) продукт, сделанный человеком, артефакты, памятники материальной культуры
2. Read the text and translate it:
While early flashing beacons were economical and a great aid for night-time navigation in clear weather, they were of no value in overcast conditions, or during the day when they weren’t even turned on. And they were sometimes difficult to locate in the distracting light of urban sprawl. These handicaps hastened the development of the LF (low frequency) navigation system.
Radio beacons in the 190 to 535 kHz radio band had formed the earliest LF navigation system. These powerful, 1500-watt beacons were spaced about 200 miles apart and defined electronic airways.
The beacons transmitted two Morse-code signals: the letter "A," • – , and its opposite, the letter "N," – • . When the aircraft was centered on the airway, or electrical beam, these two opposite Morse-code signals merged into a steady tone.
If the aircraft drifted off course to one side, the Morse code for the letter "A" could be faintly heard. The greater the drift, the stronger the "A" Morse code signal. Straying to the opposite side produced the "N" Morse code signal.
The low frequency beacon system developed the early 1950's, still in use today, consists of four main types of beacons, listed below in the order of lowest to highest transmitter power:
A) ILS APPROACH BEACONS
Sometimes called compass locators, these beacons are generally 25 watts or less.
The beacons help the pilot find and orient himself to the ILS course, so the localizer and glideslope transmissions can then take over and guide the pilot into the airport. They can be distinguished from other beacons on the air because they have 2 letter Morse code identifiers.
B) AIRPORT HOMING BEACONS
These beacons are used at airports that do not have a ILS system to serve as a general homing aid to that airport. As such they are primarily a benefit to small plane pilots, and can only be used under VFR conditions. They are most commonly also 25 watts, but some airport beacons can be up to 100 watts.
C) CROSS COUNTRY/WEATHER BROADCAST BEACONS
These beacons were put about 200 miles apart, and had a transmitter power of up to 400 watts typically. They had voice circuits to broadcast weather, usually with continuous tapes. Being on low frequencies, they could be heard on the ground, for preflight use.
D) LONG RANGE WATER CROSSING BEACONS
Most powerful and rare type of beacon. They are generally of 2000 watts and were established mainly on coastlines and islands to provide a homing signal for planes flying in from a transoceanic crossing or crossing a body of water for a few hundred miles.
All forms of low frequency homing beacons are technically obsolete in relation to VOR's and now GPS, and are largely no longer used by most pilots.
In any case, because low frequency beacons are so cheap and easy to operate as a backup, they may never completely disappear. Perhaps, similar to lighthouses, which have also been obsoleted by GPS, we should preserve a few radiobeacons for the future as historical artifacts, coming as they do from the earliest days of radio.
3. Give the equivalents, using the text:
a) проблесковый маяк, навигация в ночное время, отвлекающий свет, ускорить развитие, располагаться на расстоянии 200 миль друг от друга, передавать сигналы кода Морзе, сливаться в один звук, сбиться с курса в сторону, помочь пилоту определить свое местоположение, основное средство самонаведения, цепи передачи речевых сигналов, предполетное использование, пересечение водоемов, технически устаревшие, полностью исчезнуть.
b) flashing beacon , great aid for night-time navigation, to be of no value, to be turned on/off, to locate in the distracting light, to define electronic airways, merged into a steady tone, to drift off course, straying to the opposite side, compass locators, to be distinguished from, to serve as a general homing aid, continuous tapes, in relation to, to be no longer used by, to preserve radio beacons for the future.
4. Answer the following questions:
1) What are the advantages and disadvantages of the early flashing beacons?
2) What beacons does the earliest LF navigation system include?
3) How were the Morse-code signals transmitted?
4) When was the low frequency beacon system developed?
5) What is the main function of the ILS approach beacon?
6) What kind of beacons can serve as a general homing aid to the airport, which doesn’t have a ILS system?
7) Long Rang Water Crossing Beacons were established mainly on coastlines and islands to broadcast weather, weren’t they?
8) Will low frequency beacons disappear soon?
5. Match each word in the left-hand column with the best meaning in the right-hand column.
1. The beacons were economical and a) Long Range Water Crossing
of great value in clear weather in Beacons
night-time.
2. The beacons had the lowest b) Flashing Beacons
transmitter power they
had 2 letter Morse code
identifiers.
3. The beacons helped small plane c) ILS Approach Beacons
pilots and often had “T” type
antennas.
4. The most interesting class of beacons d) Cross Country/Weather
being on low frequencies, people were Broadcast Beacons
able to tune the beacon band on their
portable radios just to get the weather.
5. These powerful beacons could e) Airport Homing Beacons
provide a homing signal for
planes flying too far for a VHF
range.
6. Translate from Russian into English:
1) Первые маяки были не только экономичны, но и необходимы для навигации в темное время суток.
2) Радиомаяки мощностью от 190 до 535 кГц образовали первую навигационную
систему на низких частотах.
3) Маяки системы ILS отличаются самой низкой мощностью до 25 кГц.
4) Некоторые маяки используют в аэропортах, где они служат основным
средством самонаведению
5) Хотя низкочастотные системы радиомаяков уже достаточно устарели и
практически не используются пилотами, следует все же сохранить их в
качестве памятников материальной культуры для последующих поколений.
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