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Speak about amplifiers, their role in communication and branches of use




 

UNIT VI

Feeders

 

EXERCISE 1

Read and translate the text using the following words and word combinations

 

Words and word combinations to be remembered:

 

Feeder – 1)подающий механизм; питающий механизм; 2) фидер

waveguide – волновод

oscillation - колебание

to undergo - выдерживать

humidity and acing – влажность и обледенение

reflecting metallic mirror – отражательное металлическое зеркало

 

Antenna-feeder devices

Antenna-feeder devices provide receiving and transmitting electromagnetic signals. Such devices consist of antenna, which radiates and receives radio waves, and feeder. Feeder is a cable or a waveguide which conducts oscillations from generator to the transmitting antenna and from receiving antenna to the receiver. Shape, size and configuration of the device could be different and depend on the length of a radiated and received wave.

Physical characteristics of antenna are the following:

Wind load and vibration. In fact, antennas are usually placed on the roofs of buildings where wind load is maximum. So antenna’s construction and its bolting must withstand wind speed 160 km/h. Besides, antennas must be designed to undergo vibration up to 5 g (where g = 9,81 m/sec2 ).

The environmental temperature should be within – 40 ºC to + 50 ºC, so that antenna could operate continuously.

Humidity and acing (frost) shouldn’t prevail 95%, otherwise antenna’s efficiency will get worse. But afterwards, when these factors stop effecting the antenna, its properties must be possible to restore.

Mass and configuration of antenna play important part in bolting and mounting, as well as in its positioning. Antenna-feeder devices are used in systems and complexes, including wireless radio communication. There are antennas of different shapes: a piece of wire, combination of such pieces, reflecting metallic mirrors, air holes with metallic walls and wire spirals.

 

EXERCISE 2

Would you like to work at an office? Why/ Why not? Make sentences about the office. The start is given to you in the table.

It’s….. It isn’t…..
There’s a….. There isn’t a…..
There are some … There aren’t any …

Use words from the box below:

Computers office plants coffee machine small dark photographs

Bookcase very tidy windows water fountain notice board

Stationery bin

 

EXERCISE 3

Read the text about Read and translate the text about Yuzhnoye State Design Office. Make up a plan to the content of the text.

Yuzhnoye State Design Office

Over 35 years Yuzhnoye State Design Office has performed a great number of research and development activities having gained experience in creation of onboard antenna feeders (AF) intended for spacecraft and launch vehicles. High structural reliability of onboard antennas is confirmed by their long-term operation on over 100 domestic satellites including the Intercosmos family. At AF development over 50 proprietary engineering solutions protected by the national patents were applied.

Yuzhnoye State Design Office has wide experience in development of feeder tracts intended for operation as parts of antenna feeders for spacecrafts and launch vehicles. There is a long list of the elements developed: frequency selective devices (filters, diplexers, multiplexers), power dividers (combiners), coaxial and waveguide switches, wide-band waveguiding hermetic junctions, SWF sensors, break-away connectors etc. The elements operate within the frequency range of up to 10 GHz and are structurally implemented on various types of feeder tracts such as coaxial, strip and waveguide. For calculations up-to-date software is used, it enables computer analysis and synthesis of devices designed. The elements have high reliability, small dimensions and low weight. Below is the description of various configurations of antennas and feeder tract SHF-units.

Omnidirectional antennas. For the 0.3-300 Hz frequency band the electric dipole antennas are widely used as omnidirectional. For the lower frequency band section the antenna configuration with retractable electromechanic vibrator gear of up to 25 m long was developed. Self-turning vibrators of up to 8m length are also applied. For the 100-300 MHz band the V-shaped corner antenna configuration is developed$ it is intended for installation on satellite case and unfolding beams. By means of reactive elements incorporated into vibrators, dual-frequency antennas with frequency diversion of over 30% are implemented.

Near-omnidirectional antennas. This type antennas form directional pattern with weak directiveness and definite form in semisphere. Antenna configurations provide system operation within P, L, S bands and are installed in AUOS-3, AUOS-C, Sich-1M, Okean, Microsatellite etc.

Waveguide antennas. Wide range of waveguard antennas with various beam shape of directional pattern was developed. They are used directly for SC and LV, as well as irradiators for reflector antennas. A number of complex shape structures (reflector antennas irradiators, subdished) are manufactured using the method of galvanoplastic shaping after the Institute of Technical Mechanics of Academy of Science in the Ukraine.

 

 

EXERCISE 4

Answer the questions to the context of the text

· What is the name of the company?

· What products or services does this company provide?

· Where is the company located?

· Do you know anything about its activities?

· Describe current projects.

· Speak about employees.

 

EXERCISE 5

 

What do these numbers mean? Complete the notes.

1. Over 35 years____________________________activities.

2. _________________________is confirmed__________on over 100 domestic satellites including________________.

3. At AF development over 50 ___________________ protected by the national patents were applied.

4. Yuzhnoye State Design Office has _____________in development of feeder tracts intended _________as parts of antenna feeders for_____________________.

5. The elements operate ____________10 GHz and are structurally implemented _________________such as coaxial, strip and waveguide.

6. For calculations_________________, it enables computer ______________of devices designed.

EXERCISE 6

 

Read and translate the information about Taganrog radio engineering Institute. Make notes on the following points: location, activities, personnel, facilities, training and achievements

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