Radar

Question 1

What are the three units that comprise traffic radar?

Answer 1

Transmitter
Receiver
Antenna

Question 2

There are three things that can happen to a radar wave, what are they?

Answer 2

Reflected
Refracted
Absorbed

Question 3

How can you minimise the cosine effect when using radar?

Answer 3

Aiming the beam so that the angle between the radar and the target vehicle will minimise the cosine effect.

Any speed difference between true speed and the recorded speed will always be in the favour of the target vehicle.

Question 4

Who is permitted to use radar speed enforcement equipment?

Answer 4

Only police members who have been certified as trained operators are permitted to use radar speed enforcement equipment.

Completed module 70% pass.

20hrs practical instruction with approved instructor to certify competence.

Issued with certificate from Traffic Operations Support Group.

Question 5

What is the antenna component of traffic radar used for?

Answer 5

To aim the microwave beam at the area being monitored.

Question 6

Does the width of the beam remain the same the further from the transmitter it is emitted?

Answer 6

No

The further it extends the wider it becomes.

Question 7

What factors can effect the radar range?

Answer 7

Weather conditions - Rain, Mist, Fog
Local Terrain - Hills, Corners, Fences & Buildings
Road undulations will also reduce the range and cause fading to the return signal.

Question 8

How can the operator reduce the target range?

Answer 8

The range control is used to reduce range.

Question 9

What affect does vehicle size and shape have on the strength of the reflected signal?

Answer 9

The size & shape of the target vehicle’s surface will affect the information sent back to the radar unit.

The bigger the target the better it will reflect the signal.

A small, aerodynamically designed vehicle is a poor reflector, which means you will need to be closer to the unit to be picked up clearly.

Question 10

There are two major things that you must consider when selecting a stationary operating site, what are these?

Answer 10

OPERATION

SAFETY

Question 11

Establishing tracking history for all radar check requires three elements, what are these?

Answer 11

Visual Observation
Audio Confirmation
Radar Verification

Question 12

What must you carry out with your Visual Observations?

Answer 12

1. Identify the target vehicle and continue to monitor its travel
2. Confirm the target is within the radar’s range
3. Estimate the target’s speed.

Question 13

What must you carry out with your Audio Confirmation?

Answer 13

1. Listen for a clear doppler tone.
2. Check the doppler tone is consistence with the speed.
3. Check the level of the signal heard is strong and not fluctuating in audio content.

Question 14

What must you carry out with your Radar Confirmation?

Answer 14

1. Check the initial reading is consistent with visual observation and the operator estimated speed.
2. Ensure a steady target reading.
3. Check the readings are consistent with visual observation and audio tone.
4. Confirm ground speed readings by patrol speedometer.

Question 15

What are the tuning forks used for?

Answer 15

Used to simulate speed.

Each fork is stamped with an operating band and speed it will produce when struck.

It is used to test that the unit is detecting the speed accurately.

Question 16

What is the doppler shift?

Answer 16

The speed radar detects a movement between the transmitted and received signal.

The change in the frequency is known as the doppler shift.

The radar unit determines the frequency difference between the signals transmitted from the radar unit and the signals reflected from the moving target.

The change in the tone in the speaker is the doppler shift frequency.

Question 17

Why is a certified speedo required when operating traffic radar?

Answer 17

As part of the accuracy testing of the unit the speed of the patrol vehicle is checked against the patrol speed detected by the radar unit.

Before using the unit the match between the patrol speed and the speed detected by the unit must be within +/- 3km/h.

This is used to confirm unit accuracy.

Question 18

What reasons are there for loss of ground speed?

Answer 18

Heavy Rain
A wet road surface
A badly sighted antenna
Range control is turned down to low
Target vehicle travelling at the same speed as the patrol vehicle
When the hold button is released without clear road in front (the device becomes confused an no reading is shown).

Question 19

Is it a requirement to lock every speed reading when conducting an enforcement stop?

Answer 19

While it is preferred that the target vehicle speed is locked on before an enforcement stop, it is not essential.