an antenna having an em feed , a rear parabolic twist reflector and a front transreflector . the transreflector is closer to the parabolic twist reflector than the focal point of the parabolic twist reflector , and the twist reflector is defined , mounted , or otherwise formed on a parabolic surface of a base . the base is dimensioned and arranged to provide a foundation aligning an axis of the parabolic twist reflector with an axis of the antenna , and is further dimensioned and arranged to maintain substantial alignment of the feed and twist reflector with variations in ambient temperature that would otherwise produce at least one of warping and misalignment of the parabolic twist reflector in the absence of the base .