ISCET RADAR FLASHCARDS EXAM QUESTIONS AND ANSWERS LATEST UPDATE 2025-2026
To install and maintain a RADAR, you must have: - Answers GROL w/ Radar or GMDSSIM w/
Radar
Who may replace fuses and receiving type tubes and circuits in a Radar? - Answers Holder of
GROL w/ Radar
Under what circumstances can an unlicensed person operate a radar set? - Answers Only if the
Tx is a non-tunable type and when the master of the ship designated him to operate it
What Radar maintenance work may be done by unlicensed workers? - Answers None
Who is permitted to operate a ship Radar? - Answers Master of the ship, or anyone designated
by the master.
What is box 46 of EL8-A? - Answers TR Box
What is box 47 of EL8-A? - Answers RF Attenuator
What is box 48 of EL8-A? - Answers Klystron
What is box 49 of EL8-A? - Answers Crystal Detector
What is box 50 of EL8-A? - Answers Discriminator
The minimum range of a Radar is primarily determined by: - Answers The pulse width and TR
(TRL) cell recovery time
An RF mixer has what purpose in a Radar system? - Answers It converts low-level signal to a
different frequency
The switching devices most commonly used in pulse networks, and pulse transformers are/is: -
Answers SCR's and Thyratrons
Good bearing resolution largely depends upon: - Answers A narrow antenna beam in the
horizontal plane
Bearing Resolution is: - Answers The ability to distinguish two adjacent targets of equal distance.
An artificial line is used for: - Answers Determining the shape and durations of the pulses
What device is located between the magnetron and the mixer and prevents received signals
from entering the magnetron? - Answers The ATR box
The ATR Box: - Answers Prevents the received signal from entering the transmitter
When a pulse radar is radiating, which elements in the TR box are energized? - Answers The TR
, and ATR tubes
In the AFC system, the discriminator compares the frequencies of the: - Answers Magnetron
and Klystron
The purpose of the discriminator circuit in a Radar is to: - Answers Generate a corrective voltage
for controlling the frequency of the klystron local oscillator
Where is the RF Attenuator used in a Radar? - Answers Between the Magnetron and AFC section
of the receiver
What frequency is the discriminator tuned to? - Answers 30 MHz IF
The usual intermediate frequency of a shipboard Radar unit is: - Answers 30 or 60 MHz
The error voltage from the discriminator us applied to: - Answers The repeller (reflector) of the
klystron
How may the frequency of the klystron be varied? - Answers Small changes can be made by
adjusting the repeller voltage and large changes can be made by adjusting the size of the
resonant cavity
Fine adjustment of the reflex klystron are accomplished by: - Answers Varing the repeller
voltage
The pulse repetition rate (PRR) refers to: - Answers The pulse rate of the magnetron
The timer circuit: - Answers Determines the PRR, determines range markers, and provides
blanking and unblanking signals for the CRT
On what frequency is radar expected to cause interference? - Answers On most any
communication frequency
If the magnetron is allowed to operate without the magnetic field in place: - Answers It will
quickly destroy itself from excessive current flow
What radar circuit determines the pulse repetition rate (PRR)? - Answers The timer (syncronizer
circuit)
Range markers are determined by: - Answers The timer
Unblanking pulses are produced by the timer circuit. Where are they sent? - Answers To the CRT
Accurate range markers must be developed using very narrow pulses. A circuit that could be
used to provide these high-quality pulses for the CRT is a: - Answers Blocking oscillator
What determines the maximum unambiguous data: - Answers The time between the
transmitted pulses
To install and maintain a RADAR, you must have: - Answers GROL w/ Radar or GMDSSIM w/
Radar
Who may replace fuses and receiving type tubes and circuits in a Radar? - Answers Holder of
GROL w/ Radar
Under what circumstances can an unlicensed person operate a radar set? - Answers Only if the
Tx is a non-tunable type and when the master of the ship designated him to operate it
What Radar maintenance work may be done by unlicensed workers? - Answers None
Who is permitted to operate a ship Radar? - Answers Master of the ship, or anyone designated
by the master.
What is box 46 of EL8-A? - Answers TR Box
What is box 47 of EL8-A? - Answers RF Attenuator
What is box 48 of EL8-A? - Answers Klystron
What is box 49 of EL8-A? - Answers Crystal Detector
What is box 50 of EL8-A? - Answers Discriminator
The minimum range of a Radar is primarily determined by: - Answers The pulse width and TR
(TRL) cell recovery time
An RF mixer has what purpose in a Radar system? - Answers It converts low-level signal to a
different frequency
The switching devices most commonly used in pulse networks, and pulse transformers are/is: -
Answers SCR's and Thyratrons
Good bearing resolution largely depends upon: - Answers A narrow antenna beam in the
horizontal plane
Bearing Resolution is: - Answers The ability to distinguish two adjacent targets of equal distance.
An artificial line is used for: - Answers Determining the shape and durations of the pulses
What device is located between the magnetron and the mixer and prevents received signals
from entering the magnetron? - Answers The ATR box
The ATR Box: - Answers Prevents the received signal from entering the transmitter
When a pulse radar is radiating, which elements in the TR box are energized? - Answers The TR
, and ATR tubes
In the AFC system, the discriminator compares the frequencies of the: - Answers Magnetron
and Klystron
The purpose of the discriminator circuit in a Radar is to: - Answers Generate a corrective voltage
for controlling the frequency of the klystron local oscillator
Where is the RF Attenuator used in a Radar? - Answers Between the Magnetron and AFC section
of the receiver
What frequency is the discriminator tuned to? - Answers 30 MHz IF
The usual intermediate frequency of a shipboard Radar unit is: - Answers 30 or 60 MHz
The error voltage from the discriminator us applied to: - Answers The repeller (reflector) of the
klystron
How may the frequency of the klystron be varied? - Answers Small changes can be made by
adjusting the repeller voltage and large changes can be made by adjusting the size of the
resonant cavity
Fine adjustment of the reflex klystron are accomplished by: - Answers Varing the repeller
voltage
The pulse repetition rate (PRR) refers to: - Answers The pulse rate of the magnetron
The timer circuit: - Answers Determines the PRR, determines range markers, and provides
blanking and unblanking signals for the CRT
On what frequency is radar expected to cause interference? - Answers On most any
communication frequency
If the magnetron is allowed to operate without the magnetic field in place: - Answers It will
quickly destroy itself from excessive current flow
What radar circuit determines the pulse repetition rate (PRR)? - Answers The timer (syncronizer
circuit)
Range markers are determined by: - Answers The timer
Unblanking pulses are produced by the timer circuit. Where are they sent? - Answers To the CRT
Accurate range markers must be developed using very narrow pulses. A circuit that could be
used to provide these high-quality pulses for the CRT is a: - Answers Blocking oscillator
What determines the maximum unambiguous data: - Answers The time between the
transmitted pulses
