Effective height

1. The height of the center of radiation of an antenna above the effective ground level.

2. In low-frequency applications involving loaded or nonloaded vertical antennas, the moment of the current distribution in the vertical section divided by the input current.

Note: For an antenna with symmetrical current distribution, the center of radiation is the center of distribution. For an antenna with asymmetrical current distribution, the center of radiation is the center of current moments when viewed from points near the direction of maximum radiation.

Source: from Federal Standard 1037C and from MIL-STD-188