Installation, Maintenance & Repair
Subelement F
Section 44
Equipment Faults-1
When you examine the RADAR you notice that there is no target video in the center of the CRT. The blank spot gets smaller in diameter as you increase the range scale. What operator front panel control could be misadjusted?
-
TUNE.
-
Correct AnswerSensitivity Time Control (STC).
-
Anti-Clutter Rain (ACR).
-
False Target Elimination (FTE).
The STC - Sensitivity Time Control used to remove nearby clutter from the screens operates at the distance determined by the position of the STC knob.
When the range slector is switched, all objects on the display are redrawn according to the new range setting, including the distance at which the STC is de-cluttering the screen.
Last edited by jahman. Register to edit
Tags: none
Range rings on the PPI indicator are oval in shape. Which circuit would you suspect is faulty?
-
Timing circuit.
-
Video amplifier circuit.
-
Range marker circuit.
-
Correct AnswerSweep generation circuit.
TV stations often transmit test images when off the air to asist in TV set calibration.
One of the elements od the test image is a circle to test the TV's horizontal and vertical sweep's linearity and relative gain.
Last edited by jahman. Register to edit
Tags: none
What would be the most likely defective area when there is no target video in the center of the CRT and the blank spot gets smaller in diameter as your range scale is increased?
-
Correct AnswerThe TR (TRL) Cell.
-
The local oscillator is misadjusted.
-
Video amplifier circuit.
-
The IF amplifier circuit.
Question has “CRT” acronym in it. Answer has “TR” Cell in it.
Last edited by jukesj01. Register to edit
Tags: none
While the vessel is docked the presentation of the pier is distorted near the center of the PPI with the pier appearing to bend in a concave fashion. This is a primary indication of what?
-
The deflection coils need adjusting.
-
The centering magnets at the CRT neck need adjusting.
-
Correct AnswerThe waveguide compensation delay line needs adjusting.
-
The CRT filaments are weakening.
This question does not yet have an explanation!
Register to add one
Tags: none
In a RADAR using digital video processing, a bright, wide ring appears at a fixed distance from the center of the display on all digital ranges. The transmitter is operating normally. What receiver circuit would you suspect is causing the problem?
-
VRM circuit.
-
Correct AnswerVideo storage RAM or shift register.
-
Range ring generator.
-
EBL circuit.
The offending ring's position is independent of the range setting so the ring generator circuit is at fault. The Shift Register is the centerpiece of the ring generator so it must faulty and Answer B. is the right answer.
Answer A. is wrong because VRM - Variable Range marker while the problem is with a fixed range ring.
Answer C. is wrong because the offending ring is independent of range settings.
Answer D. is wrong because the EBL - Electronic Bearing Line draws a line on the display and is thus unrelated to drawing rings.
Last edited by jahman. Register to edit
Tags: none
The raster scan RADAR display has missing video in a rectangular block on the screen. Where is the most likely problem area?
-
Horizontal sweep circuit.
-
Power supply.
-
Correct AnswerMemory area failure.
-
Vertical blanking pulse.
A video memory chip is faulty and not delivering the data corresponding to a square area on the display screen, so Answer C. is the right one.
Answers A. and C. are wrong because they would affect de entire screen area and not just a specific square area.
Answer D. is wrong because the Vertical Blanking Pulse inhibits the raster from drawing anything on the screen while the raster moves diagonally from the bottom right corner of the screen to the upper left corner to start drawing a new image.
Last edited by jahman. Register to edit
Tags: none
HamStudy.org™ is copyright 2024 Signal Stuff™, All rights
reserved.
View Privacy Policy | Get help with HamStudy.org™
View Privacy Policy | Get help with HamStudy.org™