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Computer programs have been developed to calculate the radiation patterns and gain for the following types of antennas, as used by administrations, for HF broadcasting and other services: arrays of half-wave horizontal dipoles; quadrant antennas and horizontal dipoles; log-periodic antennas; tropical antennas; rhombic antennas and vertical ...
NOTE 1 – Part 1 to Annex 1 gives comprehensive and detailed information on the theoretical characteristics of HF transmitting antennas. Computer programs have been developed from the theory to calculate the radiation patterns and gain for the various included antenna types.
The vertically oriented STL antenna’s -of-8 doughnut shaped radiation pattern figure maximum is in the plane of the loop with -farfield nulls (for small loops) at right angles to the plane of the loop.
antenna is not good if it does not radiate enough signal or if it sends the signal off in the wrong direction. Our purpose here is to discuss only those features of radio wave transmission that have some bearing on the installation and maintenance of a high-frequency (HF) antenna system. B. Wavelength and Frequency
The radiation pattern shows how antennas distribute energy in space. deciBels (dB) = 10 log (power ratio) Impedance = ratio of Voltage to Current. Feed point - place where power is applied. -1 dB from the maximum gain reference value. Azimuthal Pattern. Elevation Pattern. Front-to-Back, Front-to-Side, and Front-to-Rear ratios.
investigate and verify the effective radiation pattern of a variety of types of HF antennas. The measurements have been performed by using airborne equipment. The results of these measurements on non-obstructed antennas confirm that the radiation patterns of the main beam are
Recent research efforts by SSC Pacific’s Applied Electromagnetics Branch (Code 52250) show that the APR extends to accurate measurement of normalized far-field radiation patterns of HF antennas. The normalized pattern measurement is done through a far-field extrapolation of near-field measurements.
