> The gain listed on antennas is really just telling you how directional it is, any gain above 0 means it has directionality over a perfect omni and must be ori

> The gain listed on antennas is really just telling you how directional it is, any gain above 0 means it has directionality over a perfect omni and must be oriented properly to take advantage of it. This is generally correct, but for more context ERP uses a gain in dBd which is decibels relative to a dipole antenna. A dipole is not a perfect omnidirectional antenna. A perfectly omnidirectional antenna would be an isotropic or point source antenna, which is only theoretical (no truly isotropic antenna can actually be built as far as I know, but dipoles are simple to build and widely used). Gain is measured in dBi when comparing to isotropic antennas, and EIRP (Effective Isotropic Radiated Power) would be used, not ERP. This may sound like a small nitpick, but its a pretty huge difference in practice! 1MW ERP is approximately 1.6MW EIRP.