Title :
Short medium frequency AM antennas
Author :
Trainotti, Valentin
Author_Institution :
CITEFA, Buenos Aires, Argentina
fDate :
9/1/2001 12:00:00 AM
Abstract :
Short antennas have again attracted broadcaster attention. These kinds of antennas have been used since the 1920s. At that time it was the logical antenna as a new application of this service after more than twenty years of telegraphic transmissions. Telegraphic transmissions were the most important radio communication service at that time, and because of the long range needed the lowest frequencies as possible were employed. For this reason very short antennas were used even if their size was enormous. Top loaded monopoles were very popular and this technique was employed for broadcast use before the vertical transmitting mast exhaustive study was carried on in the thirties. Nowadays a short antenna would be useful for low power applications and specially to be mounted on building tops. Of course this kind of antennas is not intended to replace the optimum monopoles or vertical dipole where maximum efficiency, maximum gain and antifading properties were achieved after exhaustive studies and after long experience theoretically and practically achieved. CFAs, short monopoles, short dipoles and short folded monopoles have been analyzed from the theoretical and practical point of view in order to choose the simplest and most efficient. model to fulfill downtown stringent requirements
Keywords :
amplitude modulation; broadcast antennas; dipole antennas; monopole antennas; radio broadcasting; transmitting antennas; 20 MHz; CFA; MF; MF broadcast transmitting antennas; building tops; low power applications; short antenna; short dipole antennas; short folded monopole antennas; short medium frequency AM antennas; short monopole antennas; Amplitude modulation; Antenna radiation patterns; Antenna theory; Dipole antennas; Frequency; Loaded antennas; Polarization; Radio broadcasting; Radio communication; Transmitting antennas;
Journal_Title :
Broadcasting, IEEE Transactions on