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Questions and Answers
What is one way that RF energy can affect human body tissue?
What is one way that RF energy can affect human body tissue?
Which of the following properties is important in estimating whether an RF signal exceeds the maximum permissible exposure (MPE)?
Which of the following properties is important in estimating whether an RF signal exceeds the maximum permissible exposure (MPE)?
How can you determine that your station complies with FCC RF exposure regulations?
How can you determine that your station complies with FCC RF exposure regulations?
What does 'time averaging' mean in reference to RF radiation exposure?
What does 'time averaging' mean in reference to RF radiation exposure?
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What must you do if an evaluation of your station shows RF energy radiated from your station exceeds permissible limits?
What must you do if an evaluation of your station shows RF energy radiated from your station exceeds permissible limits?
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What effect does transmitter duty cycle have when evaluating RF exposure?
What effect does transmitter duty cycle have when evaluating RF exposure?
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Which of the following steps must an amateur operator take to ensure compliance with RF safety regulations when transmitter power exceeds levels specified in part 97.13?
Which of the following steps must an amateur operator take to ensure compliance with RF safety regulations when transmitter power exceeds levels specified in part 97.13?
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What type of instrument can be used to accurately measure an RF field?
What type of instrument can be used to accurately measure an RF field?
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What is one thing that can be done if evaluation shows that a neighbor might receive more than the allowable limit of RF exposure from the main lobe of a directional antenna?
What is one thing that can be done if evaluation shows that a neighbor might receive more than the allowable limit of RF exposure from the main lobe of a directional antenna?
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What precaution should you take if you install an indoor transmitting antenna?
What precaution should you take if you install an indoor transmitting antenna?
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What precaution should you take whenever you make adjustments or repairs to an antenna?
What precaution should you take whenever you make adjustments or repairs to an antenna?
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What precaution should be taken when installing a ground-mounted antenna?
What precaution should be taken when installing a ground-mounted antenna?
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Which wire or wires in a four-conductor line cord should be attached to fuses or circuit breakers in a device operated from a 240-VAC single-phase source?
Which wire or wires in a four-conductor line cord should be attached to fuses or circuit breakers in a device operated from a 240-VAC single-phase source?
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What is the minimum wire size that may be safely used for a circuit that draws up to 20 amperes of continuous current?
What is the minimum wire size that may be safely used for a circuit that draws up to 20 amperes of continuous current?
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Study Notes
RF Energy and Human Health
- RF energy primarily affects human body tissue by heating it.
Estimating RF Exposure
- Key properties for estimating RF signal exposure include duty cycle, frequency, and power density. All factors are critical in determining potential MPE exceedance.
Compliance with FCC Regulations
- Compliance with FCC RF exposure regulations can be achieved through calculations based on FCC OET Bulletin 65, computer modeling, and field strength measurements.
Time Averaging in RF Exposure
- "Time averaging" refers to averaging total RF exposure over a specified time period rather than focusing on isolated instances.
Addressing Excess RF Exposure
- If RF energy from a station exceeds permissible limits, necessary action must be taken to prevent human exposure.
Transmitter Duty Cycle Impact
- A lower transmitter duty cycle allows for greater short-term exposure levels without violating safety regulations.
RF Safety Compliance Steps
- Amateur operators must perform routine RF exposure evaluations if transmitter power exceeds specified levels in part 97.13.
Measuring RF Fields
- A calibrated field-strength meter with an appropriate antenna is necessary to accurately measure an RF field.
Safeguarding Neighbors from RF Exposure
- If evaluations indicate that neighbors may receive excessive RF exposure from a directional antenna’s main lobe, precautions must be taken to ensure the antenna is not pointed in their direction.
Indoor Transmitting Antenna Precautions
- Ensure that MPE limits are not exceeded in areas occupied by people when installing indoor transmitting antennas.
Adjusting or Repairing Antennas
- Always turn off the transmitter and disconnect the feed line before making adjustments or repairs to an antenna to ensure safety.
Ground-Mounted Antenna Considerations
- Ground-mounted antennas should be installed carefully to prevent any potential RF radiation exposure exceeding maximum permissible limits.
Electrical Circuit Safety
- In a four-conductor line cord for a 240-VAC single-phase source, only the hot wires should be connected to fuses or circuit breakers.
Studying That Suits You
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Description
Test your knowledge with these flashcards covering key concepts from the Ham Radio General Class. Each card challenges you to recall vital information about RF energy effects and regulations. Perfect for studying and preparing for your exam!
