A Study of the Radiation Characteristics of Shipboard Antenna Systems (New Construction)

In general, one of the outstanding differences between transmitting antennas employed on Naval combatant vessels as compared with antennas erected on land, lies in the restricted dimensions of the Naval shipboard antennas. This is particularly true of antennas operating in the frequency range below 600 kilocycles. Where as the land establishment is capable of proportioning the antenna to obtain, to a large extent, most of the characteristics which make for efficiency, the Naval shipboard antenna must be subjugated to the exigencies of military activities. Thus it will be found that instead of antennas which may approach a quarter wave, the service is forced to employ antennas which are only a very small fraction of a wave length. For instance, an antenna 80 feet high is only 0.016 of a wave length at 200 kilocycles. 2. In the following discussion two frequency ranges are considered, frequencies below 600 kilocycles and frequencies in the range of 2,000 to 20,000 kilocycles.