The invention includes a mechanical scanning feed and a spherical lens antenna system. The mechanical feed includes a waveguide, which has a movable wall assembly that contains a guide slot. The moveable wall portion also includes an end wall that is located proximate to the guide slot to prevent leakage of the propagating energy out of the waveguide. The mechanical feed also includes a drive mechanism, which moves the moveable wall assembly along the waveguide in a direction that is parallel to the direction of propagation of the energy. This allows the guide slot to be positioned at any elevation angle to allow a portion of the propagating energy to exit through the guide slot. This in combination with the waveguide being able to be rotated 360 degrees about the spherical lens provides the antenna system with nearly spherical coverage.