Operating Safety and Good Practice
RF and electrical safety
RF energy heats body tissue; never look into an open waveguide or stand in front of a directional antenna. Exposure limits vary with frequency and are averaged over time, so calculate power density S = P/(4πr²) for a simple isotropic source and apply a safety factor for gain and near-field effects. Mains work requires isolation, RCD protection and competent help. Antennas and feedlines should be disconnected or earthed during storms, and tower work requires fall protection and a spotter.
Operating practice
Know your licence conditions: correct callsign identification, permitted power, band edges and third-party traffic rules. Keep station records, avoid causing interference, and cooperate with complaints by checking filters, power and antennas first. Use a dummy load for tests, keep batteries ventilated, and never work alone at height.
Traps and rule of thumb
Examiners test whether you understand that EMR limits are frequency-dependent, that average power matters, and that an antenna can hold dangerous voltages even at modest power. Do not assume low power means no RF hazard.
Worked example: 100 W into an isotropic antenna gives S = 100/(4π × 10²) ≈ 0.08 W/m² at 10 m, before antenna gain is considered.