Ham Radio General Class Flashcards

Questions and Answers

What is one way that RF energy can affect human body tissue?

It causes the blood count to reach a dangerously low level

It heats body tissue (correct)

It cools body tissue

It causes radiation poisoning

Which of the following properties is important in estimating whether an RF signal exceeds the maximum permissible exposure (MPE)?

Its power density

All of these choices are correct (correct)

Its frequency

Its duty cycle

How can you determine that your station complies with FCC RF exposure regulations?

By measurement of field strength using calibrated equipment

By calculation based on FCC OET Bulletin 65

All of these choices are correct (correct)

By calculation based on computer modeling

What does 'time averaging' mean in reference to RF radiation exposure?

The total RF exposure averaged over a certain time Signup and view all the answers

What must you do if an evaluation of your station shows RF energy radiated from your station exceeds permissible limits?

Take action to prevent human exposure to the excessive RF fields Signup and view all the answers

What effect does transmitter duty cycle have when evaluating RF exposure?

A lower transmitter duty cycle permits greater short-term exposure levels Signup and view all the answers

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?

Perform a routine RF exposure evaluation Signup and view all the answers

What type of instrument can be used to accurately measure an RF field?

A calibrated field-strength meter with a calibrated antenna Signup and view all the answers

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?

Take precautions to ensure that the antenna cannot be pointed in their direction Signup and view all the answers

What precaution should you take if you install an indoor transmitting antenna?

Make sure that MPE limits are not exceeded in occupied areas Signup and view all the answers

What precaution should you take whenever you make adjustments or repairs to an antenna?

Turn off the transmitter and disconnect the feed line Signup and view all the answers

What precaution should be taken when installing a ground-mounted antenna?

It should be installed so no one can be exposed to RF radiation in excess of maximum permissible limits Signup and view all the answers

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?

Only the hot wires Signup and view all the answers

What is the minimum wire size that may be safely used for a circuit that draws up to 20 amperes of continuous current?

AWG number 12 Signup and view all the answers

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.

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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!