Effective Isotropic Radiated Power (e.i.r.p). What is it?
e.i.r.p. = Pout (from TX) – losses (in antenna and feeder etc) in dB + antenna gain in dBi.
The regulations for 5 MHz in Sweden with max 15 W e.i.r.p. will have some strange consequences:
An inverted vee dipole with apex at 13 m has a gain of 6.7 dBi. If losses in tuner and feedline amount to 1 dB, Pout should be 5.7 dBs lower than 15 W or 4 W. It holds for an antenna over even ground with average conductivity.
For a vertical ¼ wave GP with 2 to 4 radials at 2 m Pout max is rather 30W.
Click on the image for a better view.
Inv vee dipole at right angle to the antenna plane: Vertical: