RF hazards and radiation exposure Flashcards
What type of radiation are VHF and UHF radio signals?
Non-ionizing radiation
How does RF radiation differ from ionizing radiation (radioactivity)?
RF radiation does not have sufficient energy to cause genetic damage
What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required?
50 watts PEP at the antenna
Which of the following an acceptable method to determine that your station complies with FCC RF exposure regulations?
All of these choices are correct
(By calculation based on FCC OET Bulletin 65
By calculation based on computer modeling
By measurement of field strength using calibrated equipment)
What is the definition of duty cycle during the averaging time for RF exposure?
The percentage of time that a transmitter is transmitting
Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?
It affects the average exposure of people to radiation
If the averaging time for exposure is 6 minutes, how much power density is permitted if the signal is present for 3 minutes and absent for 3 minutes rather than being present for the entire 6 minutes?
2 times as much
Why do exposure limits vary with frequency?
The human body absorbs more RF energy at some frequencies than at others
Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit?
50 MHz
What factors affect the RF exposure of people near an amateur station antenna?
All of these choices are correct
(Frequency and power level of the RF field
Distance from the antenna to a person
Radiation pattern of the antenna)
Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?
Relocate antennas
How can you make sure your station stays in compliance with RF safety regulations?
By re-evaluating the station whenever an item of equipment is changed
