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Subelement O
RADAR
Section 91
Components
The ATR box:
  • Correct Answer
    Prevents the received signal from entering the transmitter.
  • Protects the receiver from strong RADAR signals.
  • Turns off the receiver when the transmitter is on.
  • All of the above.

The ATR box:

Prevents the received signal from entering the transmitter.

The ATR box is the Anti-Transmit Receiver Tube. It turns off the transmitter of a radar when the radar is listening to the coming back signal, so that it prevents echoes from interfering with operations.

Opposite is the TR Tube, or Transmitter-Receiver Tube, which disconnects the receiver

For more info, please see RF Cafe site, for the article Module 18 - Radar Principles Navy Electricity and Electronics Training Series (NEETS)

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What is the purpose or function of the RADAR duplexer/circulator? It is a/an:
  • Coupling device that is used in the transition from a rectangular waveguide to a circular waveguide.
  • Correct Answer
    Electronic switch that allows the use of one antenna for both transmission and reception.
  • Modified length of waveguide that is used to sample a portion of the transmitted energy for testing purposes.
  • Dual section coupling device that allows the use of a magnetron as a transmitter.

What is the purpose or function of the RADAR duplexer/circulator? It is a/an:

Electronic switch that allows the use of one antenna for both transmission and reception.

It is a binary switch, either Tx or Rx.

The duplexer, an electronic-based tool, switches direction of communication, such as send/receive, on a single wire.

The radar works by changing from transmitting to receiving. The duplexer makes use of a single antenna by this switching.

The circulator scans ports for incoming data, and can be used to work like a duplexer, by switching between transmission and receiving.

For more information, please see TutorialsPoint site for the article Radar Systems - Duplexers

Also, see Wikipedia's article Duplexer

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What device can be used to determine the performance of a RADAR system at sea?
  • Correct Answer
    Echo box.
  • Klystron.
  • Circulator.
  • Digital signal processor.

What device can be used to determine the performance of a RADAR system at sea?

Echo box.

The echo box is used to measure the power of the transmitter, so that it can be fine tuned. It works like an acoustic guitar box, amplifying the strength of the pulled string frequency. The echo box is called a cavity resonator, as it amplifies electromagnetic energy from transmission of an antenna. The amplified signal is received by a radar.

Key factors affecting the resonance of the echo box include how the cavity is tuned and the amount of signal strength fed into the resonance box. Using the echo box for testing helps to avoid consideration of atmospheric condition, experience in performance of actual radar operations. It is very useful when testing at sea, as there are no objects to for the radar to aim.

For more information, please see Tpub site for the article The Echo Box

Also see Maritime site for the article on radar's SPECIFIC EQUIPMENT, and use CTRL-F to search on "Echo Box."

Please see the Man FAS org site for the Electronics Material Officer Course, and use CTRL-F to search on "Echo Box."

For in-depth info, please see Navy Radio site, for the unclassified document called the Echo Box Design Handbook, Theory and Practice of Echo Box Design Survey of Existing Cavities. It is a pdf document of 426 pages, so it takes a bit of time to pull up.

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What is the purpose of a synchro transmitter and receiver?
  • Synchronizes the transmitted and received pulse trains.
  • Prevents the receiver from operating during the period of the transmitted pulse.
  • Correct Answer
    Transmits the angular position of the antenna to the indicator unit.
  • Keeps the speed of the motor generator constant.

What is the purpose of a synchro transmitter and receiver?

Transmits the angular position of the antenna to the indicator unit.

The device synchronizes the Tx and Tr to prevent one bleeding into the other. The Synchro transmitter stands for Synchronous transmitter. These devices are variable transformers.

The synchro receiver changes "angular position" of an electrical motor into an electrical signal, and is otherwise referred to as an "electromagnetic transducer."

Transducers change one form of energy into another, unlike transmitters that create electromagnetic waves.

The "indicator unit" is a term for radar display.

The answer basically says that signals picked up by radar show up on radar display.

For more information, please see The Knowledge Burrow site for the article What is the purpose of a synchro transmitter and receiver?

See Radar Tutorial EU article Synchros

Also, see Wikipedia's article Synchro, and the article called Radar display

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Digital signal processing (DSP) of RADAR signals (compared with analog) causes:
  • Improved display graphics.
  • Correct Answer
    Improved weak signal or target enhancement.
  • Less interference with SONAR systems.
  • Less interference with other radio communications equipment.

Digital signal processing (DSP) of RADAR signals (compared with analog) causes:

Improved weak signal or target enhancement.

DSP performs many functions fast. Improving weak signals or target enhancement results from application of digital filters that reduce or eliminate environmental factors and noise, that even weak signal echos can become recognizable.

DSP helps to clear up unclear data related to the Doppler effect. It is especially time effective in using data from successive radar measurements.

For more information, please see the ee.iitb.ac.in site for the pdf document of DSP Applications in Radar

The Iopscience.iop.org pdf document Application of DSP Technology in Radar Signal Processing

The Ijera site for the pdf document of Application Of Digital Signal Processing In Radar Signals

And, see the Radar Tutorial EU site for the article on Radar Signal Processor.

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The component or circuit providing the transmitter output power for a RADAR system is the:
  • Thyratron.
  • SCR.
  • Klystron.
  • Correct Answer
    Magnetron.

The component or circuit providing the transmitter output power for a RADAR system is the:

Magnetron.

This key device transmits the strength of the signal.

For more information, please see Wikipedia's article on Cavity magnetron

Also, see Radar Tutorial EU site for the very well illustrated article Magnetron

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