Start with the practical answer: A link budget adds transmitter power and antenna gains, then subtracts feed-line, connector, path, polarization, obstruction, and system losses in decibels; every 3 dB is approximately a factor of two in power.
What changes the result
At VHF/UHF, antenna height, terrain and Fresnel clearance, polarization, feed-line loss, connectors, and small geometric changes often dominate practical coverage.
The mistake to avoid
Do not infer guaranteed range from free-space math, one repeater contact, visual line of sight, or a high-gain number without pattern and loss context.
Use this operating sequence
Define both station locations and heights, mode and polarization, feed-line loss, terrain, and required margin; then test repeatable positions and record results.
Source boundary
Current controlled CKB RF engineering, VHF/UHF, operating, and diagnostic references. Confirm current local coordination, band plans, satellite data, and equipment documentation before operating.
