Enter your Transmitter Output Power, Antenna Gain, Cable Loss, and Additional Losses into this EIRP Calculator to find your system's Effective Isotropic Radiated Power — returned as EIRP in Watts, dBW, and Effective Radiated Power so you can evaluate exactly how much signal your antenna is pushing out.
EIRP
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EIRP (Watts)
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EIRP (dBW)
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Effective Radiated Power
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EIRP (Effective Isotropic Radiated Power) is the total power that would need to be radiated by an isotropic antenna to produce the same signal strength in a given direction. It's crucial for satellite communications, RF link budgets, and regulatory compliance.
EIRP = Transmitter Power + Antenna Gain - Cable Losses - Additional Losses. All values should be in dB units (dBm, dBi, dB) for logarithmic addition and subtraction.
dBm is power referenced to 1 milliwatt, dBW is referenced to 1 watt (dBW = dBm - 30), and Watts is linear power. dBm and dBW are logarithmic units that make calculations easier.
Cable losses vary by type and length. Coaxial cables typically have 0.1-1 dB per meter, while waveguides have lower losses. Always measure or calculate losses for your specific cable type and length.
Higher antenna gain increases EIRP proportionally. A 3 dB gain increase doubles the effective radiated power. Directional antennas focus power in specific directions, increasing EIRP in those directions.
Consider losses from connectors (0.1-0.5 dB each), splitters, filters, circulators, and other RF components in your system. These can add up significantly in complex systems.
No, ERP uses a dipole antenna as reference (2.15 dBi gain), while EIRP uses an isotropic antenna (0 dBi). EIRP = ERP + 2.15 dB. Satellite communications typically use EIRP.
WiFi routers: 20-30 dBm EIRP, Cellular base stations: 40-60 dBm, Satellite uplinks: 50-70 dBm, GPS satellites: 25-30 dBm EIRP at Earth's surface.