Of course, an antenna is not an amplifier. Antenna "gain" is obtained by forcing the radiation into a pattern, where more of the energy is "squeezed" into the direction into which we want it to go and therefore less goes to where we don't want it to go. So, in the case of the long wire with its fixed orientation, in some directions (azimuths) it will produce a "loss" instead of a gain! Harvey/W4TG