Question T0C07
From subelement T0 - T0C
What hazard is created by touching an antenna during a transmission?
Why is this correct?
RF burns to skin occur when concentrated RF energy heats tissue at the point of contact. Unlike electrocution (which requires dangerous voltage/current flow) or radiation poisoning (which requires ionizing radiation), RF burns result from the heating effect of non-ionizing electromagnetic energy. Radio signals don't carry lethal electrical current like power lines, and they're non-ionizing radiation that can't cause cellular damage like X-rays. The burn happens because RF energy converts to heat in body tissue.
Memory tip
Remember the heating mechanism: RF energy acts like a localized microwave, converting electromagnetic energy to thermal energy in tissue. This distinguishes RF hazards from electrical shock hazards—it's about energy conversion, not current flow through the body.
Learn more
RF burns demonstrate why antenna placement and operational procedures matter in amateur radio practice. Even QRP stations can cause burns due to concentrated field strength at feed points. This is why proper station design includes keeping antennas away from operating positions and using remote antenna switches. Understanding RF heating helps explain why maximum permissible exposure limits vary by frequency—the human body absorbs RF energy differently across the spectrum, making some frequencies more thermally hazardous than others.
Think about it
Why do you think RF burns can occur even at relatively low power levels, and what does this tell you about the relationship between power, antenna design, and field concentration?