Free standing MF antennas for shipboard use usually have not, in the past, fulfilled the existing international requirements of being able to provide a field strength of 30 millivolts per meter at a distance of one nautical mile on a frequency of 500 KHZ. This field strength must be achieved when using tramsmitters having power outputs from 200 to 1000 watts. A new MF/HF antenna designed with the aid of a computer and described here utilizes a maximum height of 15.2 meters and maximum diameter of 6.1 meters together with top loading, center loading, and an elevated feed point to result in a low "Q' makes it possible to provide a high enough antenna efficiency and bandwidth to meet the radiation requirements on the emergency frequency of 500 KHZ. Additionally it reduces the voltages on the antenna and makes the antenna less susceptible to losses from salt water spray. The elevated feed point reduces the RF danger to personnel. It increases the mechanical strength of the antenna. The elevated feed point is well suited to the extra long insulator which is used for the purpose of increasing the leakage path and voltage breakdown path across the antenna. Finally, it increases the frequency at which elevation plane patterns commence to "breakup", thus improving the performance of the antenna in the 2 - 25 MHZ band.

  • Supplemental Notes:
    • Paper part of a five volume Set-Price $20.00, Symposium Papers RTCM Assembly meeting, April 26-27-28, 1976, San Diego, California.
  • Corporate Authors:

    Radio Technical Commission for Marine Services

    Washington, DC  United States 
  • Authors:
    • Osborne, A I
    • Sliger, R H
    • Anderson, M V
  • Publication Date: 1976-4

Media Info

  • Pagination: 13 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00148491
  • Record Type: Publication
  • Source Agency: Radio Technical Commission for Marine Services
  • Report/Paper Numbers: V1
  • Files: TRIS
  • Created Date: Feb 23 1977 12:00AM