Basic Radar Principles Quiz

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Questions and Answers

What does pulse recurrence rate refer to?

The ratio of pulse width to pulse repetition period

The number of cycles per second

The delay known as fly-back or dead time

The number of pulses per second (correct)

Which is the most suitable radar for measuring short ranges?

Continuous wave primary (correct)

Centimetric pulse

Millimetric pulse

Continuous wave secondary

The definition of a radar display will be best with:

Narrow beam width and narrow pulse width (correct)

Wide beam width and narrow pulse width

Narrow beam width and wide pulse width

Wide beam width and wide pulse width

Attenuation of radio waves means:

The weakening of the radiated waves Signup and view all the answers

The factor that determines the minimum range of a radar is:

Pulse length Signup and view all the answers

A monochrome radar operating in the contour mode ___ and indicates them as hollow centres:

Cancels returns above the iso-echo level Signup and view all the answers

On what principle does primary ATC radar work?

Pulse technique Signup and view all the answers

What is the primary factor that influences the maximum unambiguous range of primary radar?

pulse recurrence rate Signup and view all the answers

If a primary radar facility aims to detect targets up to 200 NM, what is the maximum pulse repetition frequency it can use?

405 pps Signup and view all the answers

What describes the interval in time between two consecutive radar pulses?

pulse recurrence period Signup and view all the answers

What is the main benefit of using continuous wave radar over pulsed radar systems?

elimination of minimum range restriction Signup and view all the answers

Which factor primarily affects the maximum range of primary radar systems?

pulse recurrence frequency Signup and view all the answers

Which principle does a primary radar operate on?

pulse technique Signup and view all the answers

What is the speed of a radio wave expressed in nm/sec?

161,842 Signup and view all the answers

What type of aerial would best receive a radio wave with a horizontal magnetic component?

vertical aerial Signup and view all the answers

What governs the minimum detection range of a pulsed radar?

pulse length Signup and view all the answers

What does Doppler shift signify in radar technology?

changes in wave frequency Signup and view all the answers

Which statement is true regarding the interaction of radio waves with objects?

They are reflected by metallic objects with a size compatible to the wavelength. Signup and view all the answers

What primarily affects the maximum range of a pulse radar system?

The pulse repetition frequency. Signup and view all the answers

The Pulse Recurrence Rate (PRR) in radar technology refers to what?

The number of pulses emitted in a given time period. Signup and view all the answers

One significant advantage of Continuous Wave (CW) radar systems over Pulse radar systems is?

They do not have a minimum detection range. Signup and view all the answers

What is the primary advantage of using a slotted scanner in radar systems?

It helps to reduce side lobes and directs more energy into the main beam. Signup and view all the answers

To double the effective range of a primary radar, by what factor must the power output be increased?

By a factor of 16. Signup and view all the answers

What is a common misconception regarding the effect of frequency on radar systems?

High frequencies require smaller antennas. Signup and view all the answers

Which of the following describes a factor that does NOT affect radar range?

Type of radar display used. Signup and view all the answers

What does pulse length primarily determine in a primary radar using pulse technique?

Minimum measurable range Signup and view all the answers

How does pulse recurrence frequency (PRF) influence a primary radar system?

Determines maximum theoretical range Signup and view all the answers

If a radar system operates with a pulse recurrence frequency of 400 pps, what is the maximum theoretical range?

202 nm Signup and view all the answers

What is the pulse recurrence frequency (PRF) if the pulse interval is 5 microseconds?

200 KHz Signup and view all the answers

What primarily determines a primary radar's ability to accurately measure target range?

Pulse length Signup and view all the answers

What is the relationship of the grid potential in a cathode ray tube?

Negative with respect to the cathode Signup and view all the answers

What does a parabolic reflector's beam width depend on?

Transmitted frequency Signup and view all the answers

What happens if a radar has a pulse length of 4μs?

600 metres of minimum range Signup and view all the answers

What technique is utilized by primary radar employing a single aerial dish?

Pulse technique Signup and view all the answers

What wavelength range is characteristic of short-range aerodrome radars?

Centimetric Signup and view all the answers

Study Notes

Radar Principles Overview

Radio waves are reflected by metallic objects compatible with their wavelength.
The pulse repetition frequency (PRF) primarily affects the maximum range of pulse radar.
Pulse Recurrence Rate (PRR) signifies the number of pulses sent per second.

CW vs. Pulse Radar

Continuous Wave (CW) radar eliminates minimum range restrictions, unlike pulse radar.
CW equipment is often smaller; however, it may be more complex and potentially less reliable than pulse radar systems.

Pulse Characteristics

A slotted scanner reduces side lobes, directing more energy into the main beam.
To double the effective range of primary radar, the power output must increase by a factor of 16.
Maximum unambiguous range is primarily determined by pulse recurrence rate.

Timing and Length

The time interval between consecutive pulses is referred to as the pulse recurrence period.
Pulse length impacts minimum measurable range; a longer pulse length results in a higher minimum range.
PRF affects the maximum theoretical range, allowing the radar to detect targets correctly at various distances.

Doppler Shift and Signal Reception

Doppler shift refers to changes in frequency measured at the receiver due to the relative motion between the radar and target.
A radio wave with a horizontal magnetic component is best received by a vertical aerial.

Cathode Ray Tube Functionality

In Cathode Ray Tubes, the grid controls brilliance for optimal display quality.
The grid potential in a CRT is negative relative to the cathode, helping define the electron stream behavior.

Target Classification and Measurement

Short pulse lengths with narrow beams offer the best screen resolution in primary radar systems.
Azimuth resolution depends on beam width and pulse length; shorter pulse lengths lead to finer resolution.
Effective radar operation involves a balance between pulse length, power output, and transmission frequency.

Radar Frequency and Range Limitations

Primary radar using pulse technology operates based on pulse techniques.
Continuous wave radars are suited for measuring short ranges effectively, thanks to their design.
The factor determining a radar’s minimum detection range revolves around pulse length.

Attenuation and Wave Characteristics

Attenuation refers to the weakening of radiated waves, impacting radar detection capabilities.
Short-range aerodrome radars typically utilize centimetric wavelengths to optimize performance.

Summary of Key Facts

Radar’s effectiveness relies on a mix of power output, pulse characteristics, and operational frequency.
Understanding the principles of PRF, pulse length, and their implications is crucial for radar system operation.
Effective discrimination and detection of targets hinge upon optimizing beam width and pulse settings.

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Description

Test your knowledge on basic radar principles and pulse techniques through this focused quiz. Explore concepts related to radio waves, their behavior, and maximum range factors in radar systems. Perfect for aviation and radar system enthusiasts!