System Troubleshooting & Maintenance Flashcards

A satellite dish experiences intermittent signal loss only between 11 AM and 2 PM local time during certain months. What phenomenon is most likely responsible?

Answer: Sun outage caused by solar interference when the sun aligns behind the satellite

Sun outages occur when the sun passes directly behind a geostationary satellite relative to the receive antenna, flooding it with solar noise.

When testing coaxial cable continuity in a satellite system, a technician measures 0 ohms between center conductor and shield. What does this indicate?

Answer: A short circuit between the center conductor and shield

Zero ohms between center conductor and outer shield indicates a dead short, which will prevent signal transmission and may damage connected equipment.

A DVB-S2 receiver locks onto a signal but immediately loses lock repeatedly. Which modulation/coding parameter mismatch is most likely causing this?

Answer: Incorrect symbol rate entered in the receiver

An incorrect symbol rate setting causes the demodulator to sample at the wrong rate, preventing stable carrier lock even when frequency is correct.

What is the recommended method for waterproofing an outdoor F-connector on a satellite coaxial cable?

Answer: Use self-amalgamating tape over a weatherproof boot or wrap with self-fusing silicone tape

Self-amalgamating or self-fusing silicone tape creates a waterproof seal around the connector without leaving adhesive residue that can trap moisture.

A satellite technician is called to service a system where the IRD shows a signal but no audio is present on any channel. What is the most likely cause?

Answer: Audio decoding format mismatch (e.g., Dolby AC3 with no license)

If video is present but audio is absent on all channels, an audio codec license issue (such as AC3/Dolby) or audio output configuration mismatch is the most common cause.

During a site survey for a new VSAT installation, which tool is essential for determining dish pointing angles?

Answer: A satellite finder meter combined with a compass and inclinometer

A satellite finder provides real-time signal feedback while a compass sets azimuth and an inclinometer sets the elevation angle for dish alignment.

What maintenance schedule is generally recommended for inspecting outdoor satellite dish mounting hardware in a harsh coastal environment?

Answer: Annually at minimum, with quarterly visual checks recommended

Coastal salt air accelerates corrosion of mounting hardware, requiring more frequent inspection cycles than inland installations to prevent structural failures.