English: A widely-used type of reflective array
television antenna, the Channel-Master model 325-2 from 1954, used to receive US VHF analog television channels 2 to 13, 54 to 213 MHz. It consists of multiple
folded dipole driven elements (on left) connected by a 300Ω
twin lead feedline to the television set, mounted in front of a flat grid reflector of horizontal rods. The reflector serves to reflect the radio waves back toward the dipoles, increasing the
gain. Two different lengths of folded dipole and reflector rods are used to cover the entire VHF band. The VHF television band is divided into two subbands: VHF low (
Band I), channels 2-6, 54-88 MHz, and VHF high (
Band III), channels 7-13, 174-213 MHz. These bands are too widely separated in frequency to be covered by a single set of antenna elements. The two large folded dipoles, along with the longer reflector rods, cover the low band, while the 4 smaller dipoles, and the shorter reflector rods cover the high band. The elements are devided into two stacked "bays" which increases gain. A TV antenna like this that covered all the VHF channels was called an "all-VHF" antenna. Graphs by Channel-Master on p. 82 show the antenna has a gain of ~5 dBd over channels 2-6, 8-9 dBd over channels 7-13, and up to 9 dBd on portions of the UHF band. The advantage of the reflective array was that it achieved the high gain needed for fringe reception without the narrow
bandwidth of the common Yagi antennas.
Caption: "
An all-VHF band TV antenna, two-bay array, with reflector screen."