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EIRP & ERP
Combine transmit power, feed-line loss and antenna gain.
HB3YAQ · Ajdin HadzicLearning to take awayhttps://hb3yaq.ch/en/tools/eirp
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Formula & context
EIRP = P · 10^((GdBi − L)/10); ERP = EIRP / 10^(2.15/10)
EIRP references an isotropic radiator; ERP references a half-wave dipole. Both describe equivalent radiated power in the direction of the stated gain.
A worked example
With 0 dB feed loss and 2.15 dBi gain, ERP equals the entered transmit power.
Assumptions & limits
Calculated quantities, not a check of permitted power or exposure limits. Gain direction, polarisation and actual losses must match the inputs.
Antenna gain, dBi and EIRPUnderstand the reasoning →From reading to experimenting
EIRP & ERP
With 0 dB feed loss and 2.15 dBi gain, ERP equals the entered transmit power.
Open example with starting values →Transmit power: 5 W · Feed-line loss: 0 dB · Antenna gain: 2.15 dBiBack to the learning article →Then change exactly one value. Compare the result and use the formula to explain why it changes. The model limits below the calculator also apply here.