NEC-LIST: Half Rhombic Antennas

Mary

Rhombic antennas were popular with radio amateurs in the 30s, 40s and 50s and
there is considerable information on their construction in various amateur
publications, though not much theory.

A good reference is the 8th edition of the ARRL Antenna Book, 1956 published
by the American Radio Relay League, Hartford, Conneticut USA.

A more recent reference is the ARRL Antenna Book , 18th Edition 1997,
available from the SA Radio League at Panorama, Honeydew.

Reference Data for Radio Engineers, 6th Edition pages 27-11 and 27-12
published by Howard Sams references "Rhombic Antenna Design" by A.E. Harper
published by D Van Nostrand and Company, New York; 1941.

Frederick Terman, "Radio Engineers Handbook" , McGraw Hill, 1943 pages 805 -
806 provides a little more information. There is a copy of this book in the
Wits library.

If you are unable to find the information I can copy the relevant pages and
email them to you.

Rhombics have variously been called "squashed terminated loops" dual V beams.
and extended long wires. They can be both resonant or non-resonant structures.
A Vee beam is not truly a half Rhomic because it does not have the
characteristic termination associated with a Rhombic. However a pair of long
wires fed in the form of a Vee can each be terminated to change the direction
of radiation by 180 degrees and to improve the multi-frequency
characteristics. A non-resonant terminated long wire is a travelling wave
antenna.

I hope this helps

Chris Turner
G4HKP / ZS6GM

Chris Turner IEng MIIE
tel/fax: +44 1494 784547
mob: +44 7812 174 133
email: turner.c_at_virgin.net

  Message: 2
  From: "Mary Honnet" <maryhonnet_at_iafrica.com>
  To: <nec-list_at_gweep.ca>
  Date: Thu, 4 Apr 2002 19:20:52 +0200
  Subject: NEC-LIST:Half-Rhombic Antennas

  Hi,

  I am doing a 4th year Electrical Engineering project for my Antennas course
  (University of the Witwatersrand, Johannesburg, South Africa). My project
  involves writing a SuperNEC assembly for a half-rhombic or vee antenna and
  comparing the simulated results to other results found on the internet and
in
  journals etc.

  At the moment I am looking for journal articles about half-rhombic
antennas,
  and particularly for results of the performance of these antennas. I have
  found one journal article, "A Broadband Antenna Array for Sea Scatter
  Measurements", Mark, T. MA, IEEE Transactions on Antennas and Propagation,
  1976, AP-24, but am looking for more to suppliment my report.

  Please let me know if you know of such articles, or other sources of
results
  for the antenna.

  Thanks!
  Mary Honnet

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