Amateur ExtraE0A03
Over what range of frequencies are the FCC human body RF exposure limits most restrictive?
C
Answer
Safety
Type
A
300 kHz - 3 MHz
B
3 - 30 MHz
C
30 - 300 MHz
D
300 - 3000 MHz
Answer Notes
The human body absorbs RF energy most efficiently in the VHF range, specifically between 30 MHz and 300 MHz. This happens because a typical adult's height makes them act like a resonant dipole antenna for wavelengths in this band.
Because of this high absorption rate, it takes much less RF energy to heat the body's tissues. Therefore, the FCC sets the Maximum Permissible Exposure (MPE) limits lowest—making them the most restrictive—in the 30 MHz to 300 MHz range to protect against RF heating.
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When evaluating RF exposure levels from your station at a neighbor’s home, what must you do?
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When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?