CMRT Radar System Fundamentals 2

Question 1

What is the primary purpose of the radar duplexer in a marine radar system?

Accepted Answer

Switch the antenna between transmit and receive modes to protect the receiver

Answer

The duplexer acts as a transmit/receive switch, connecting the antenna to the transmitter during transmission and to the receiver immediately after, protecting the sensitive receiver from the high-power transmit pulse.

Question 2

In radar terminology, what does 'range resolution' refer to?

Accepted Answer

The ability to distinguish between two targets at the same bearing but different ranges

Answer

Range resolution is the radar's ability to display two separate targets at the same bearing as distinct returns rather than merging them into one; it is primarily determined by pulse width.

Question 3

Which component in a magnetron-based radar generates the high-frequency microwave energy?

Accepted Answer

Magnetron oscillator

Answer

The magnetron is a crossed-field vacuum tube oscillator that converts DC power into microwave energy at the radar's operating frequency, typically in the X-band (9–10 GHz) for marine radars.

Question 4

What effect does increasing the pulse repetition frequency (PRF) have on maximum unambiguous range?

Accepted Answer

Decreases maximum range because the listening period between pulses shortens

Answer

Higher PRF means shorter intervals between pulses, so echoes from distant targets may return after the next pulse is sent, causing range ambiguity and effectively reducing unambiguous range.

Question 5

What is the function of the radar's intermediate frequency (IF) amplifier stage?

Accepted Answer

Amplify the mixed-down received signal before detection

Answer

The IF amplifier provides most of the receiver's gain and selectivity by amplifying the signal after it has been down-converted from microwave frequency to a fixed intermediate frequency.

(CMRT) Certified Marine Radar Technician Practice Test

(CMRT) Certified Marine Radar Technician Practice Test

CMRT Radar System Fundamentals 2