In a reflector antenna[?], the relative reduction in the effective aperture of the antenna caused by the masking effect of other antenna parts, such as a feed horn or a secondary reflector, which parts obstruct the radiation path.
... and 4,197 families residing in the town. The population density is 1,058.4/km² (2,740.4/mi²). There are 5,574 housing units at an average density of ...