The spatial, diurnal and seasonal distribution of the modulation of a particular type of Sq(H) in the equatorial regions is examined. It appears most clearly as an abnormal depression of Sq(H) in the afternoon hours, sometimes resulting in the reduction of the H component well below its nighttime values. These abnormal depressions of Sq(H) occur at about the same local time in a very narrow zone (at least ±4° dip latitude) flanking the dip equator. They occur more frequently from noon to dusk in the months around the December solstice. General considerations of their characteristics are consistent with some associations with the lunar tide. However, detailed comparison of the time of maximum depression with the time of minimum geomagnetic lunar tide is not consistent with its association with the lunar tide. Some evidence from f₀F₂ suggests that the depressions arise from modulation or reversal of the electric field at the equatorial electrojet regions of the ionosphere.