SBCA Equipment Setup 3 — Questions and Answers
Question 1: What is the recommended grounding method for a satellite dish mast according to NEC Article 810?
- Connect the mast to the nearest metal water pipe only
- Bond the mast to the home's grounding electrode system with a ground block and AWG 10 copper wire (Correct answer)
- Bury a dedicated ground rod under the dish with AWG 14 wire
- Ground the LNB directly to the receiver chassis
Correct answer: Bond the mast to the home's grounding electrode system with a ground block and AWG 10 copper wire
NEC 810 requires the dish mast to be bonded to the home's existing grounding electrode system using a ground block and minimum AWG 10 copper conductor.
Question 2: A customer reports their HD receiver shows 'Searching for Satellite Signal' after a heavy snowfall. What is the most likely cause?
- LNB failure due to cold temperatures
- Snow accumulation on the dish reflector blocking the signal (Correct answer)
- Receiver firmware corruption
- Coaxial cable frozen inside the conduit
Correct answer: Snow accumulation on the dish reflector blocking the signal
Snow and ice accumulation on the dish surface block the microwave signal path, causing signal loss that resolves once the dish is cleared.
Question 3: What is the function of a voltage-passing splitter in a satellite distribution system?
- Splits the signal while blocking DC voltage on all ports
- Passes DC voltage on one port to power an amplifier or LNB (Correct answer)
- Converts single-cable SWM to dual-cable legacy
- Equalizes signal levels across all output ports
Correct answer: Passes DC voltage on one port to power an amplifier or LNB
A voltage-passing splitter allows DC power (used to power inline amplifiers or LNBs) to pass through one designated port while splitting the RF signal.
Question 4: When connecting multiple satellite receivers using a multiswitch, what signal does the IRD send to the multiswitch to select the correct LNB input?
- A 28 V DC pulse
- DiSEqC commands or 13/18 V DC switching signals (Correct answer)
- An IP command over coax
- A 5 V logic signal via the F-connector center pin
Correct answer: DiSEqC commands or 13/18 V DC switching signals
Receivers use DiSEqC protocol messages or 13 V / 18 V DC voltage levels to instruct the multiswitch which satellite position and polarization to pass.
Question 5: Which type of LNB is required to receive signals from multiple orbital positions using a single dish equipped with multiple feeds?
- Quad LNB
- Universal LNB
- Multi-satellite LNB or LNBF combo (Correct answer)
- Wideband (WBIF) LNB
Correct answer: Multi-satellite LNB or LNBF combo
Multi-satellite LNBFs or offset multi-feed assemblies allow a single dish to collect signals from two or more satellites at different orbital slots simultaneously.
Question 6: A technician measures -65 dBm at the receiver input. If the cable run has 8 dB of loss, what was the signal level at the start of the cable?
- -57 dBm (Correct answer)
- -73 dBm
- -65 dBm
- -53 dBm
Correct answer: -57 dBm
Adding the cable loss back: -65 dBm + 8 dB = -57 dBm at the cable's input end.
Question 7: What is the primary reason satellite dish installations require precise azimuth alignment within fractions of a degree?
- Geostationary satellites occupy extremely narrow orbital slots separated by 2° or less (Correct answer)
- LNBs have a very narrow beam acceptance angle of less than 0.1°
- The Earth's rotation shifts the satellite position continuously
- FCC regulations mandate alignment within 0.5° for licensing compliance
Correct answer: Geostationary satellites occupy extremely narrow orbital slots separated by 2° or less
Adjacent geostationary satellites are spaced as close as 2° apart, so even small azimuth errors can cause interference or signal loss to the intended satellite.
SBCA Equipment Setup 3
What is the recommended grounding method for a satellite dish mast according to NEC Article 810?