Abstract :
The development of transmitting aerials for television broadcasting in Band I is surveyed. Reference is made to the increase of gain, and to the splitting of the aerial system for increased flexibility and reliability. Aerials having directional radiation characteristics have been required for filling gaps in the service areas of other stations, and giving adequate protection against interference with other services. Measurement techniques and the permissible variation of reflection coefficient and radiation pattern over the video band are considered. Future developments discussed include the use of higher frequencies to obtain higher gains. The problem of giving an adequate service in areas near the mast will thus be increased and the maximum possible useful gain which can be obtained from an aerial of given height, and the degree to which a practical aerial can approach this condition, are discussed. Measurements on scale models are discussed.
