Equipment & Troubleshooting Flashcards
7 cards from real CBT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Equipment & Troubleshooting flashcards as text
A cable TV headend technologist discovers the downstream QAM channel has a high MER (Modulation Error Ratio) degradation. Which impairment is LEAST likely to cause this?
Answer: Correct input signal level within specification
A signal level within specification does not cause MER degradation; noise, phase noise, and other impairments do.
An IP-based broadcast router using SMPTE ST 2110 is dropping multicast packets intermittently. What network component should be checked first?
Answer: IGMP snooping configuration on the network switch
SMPTE ST 2110 relies on IP multicast, and incorrect IGMP snooping configuration is a common cause of dropped or undelivered multicast streams.
A technologist is using a Bird wattmeter to measure power. The element reads lower than expected. What is a common reason for this discrepancy?
Answer: The element is inserted in the reverse direction
Bird thruline wattmeters are directional; inserting the element reversed causes it to read reflected power instead of forward power.
Which protocol is used to synchronize clocks in an IP broadcast facility to sub-microsecond accuracy for SMPTE ST 2110?
Answer: PTP (Precision Time Protocol) IEEE 1588
PTP IEEE 1588 provides the sub-microsecond synchronization required for sample-accurate media transport in professional IP broadcast environments.
A broadcast technologist notices hum bars rolling through a video monitor. The hum frequency is 60 Hz. What is the MOST likely cause?
Answer: Ground loop introducing AC power-line interference into the video path
60 Hz hum bars in video are a classic symptom of a ground loop where different ground potentials create a current path through the video cable shield.
A transmitter site experiences repeated RF connector failures at the junction between the rigid coaxial line and the flexible jumper. What is the MOST likely contributing factor?
Answer: Thermal cycling causing expansion/contraction stress at the connector
Repeated heating and cooling cycles cause different metals to expand and contract at different rates, fatiguing connector joints and causing failures over time.
What is the function of an automatic transfer switch (ATS) at a broadcast transmitter site?
Answer: It automatically transfers the electrical load between utility power and a generator during an outage
An ATS monitors utility power and automatically connects the generator to the facility load when the utility fails, restoring power without manual intervention.