When to use: Use to calculate Effective Isotropic Radiated Power (EIRP) — the total power an antenna system appears to radiate in its strongest direction, relative to an isotropic radiator. EIRP = TX Power − Cable Loss − Connector Loss + Antenna Gain. Checked against FCC Part 15, 90, and 24 limits for compliance. Required for FCC applications, NFPA 1221 BDA submittals, and any RF system design. Use with the Link Budget calculator for complete coverage analysis.