Design a rhombic antenna to operate at 20mhz when the angle of elevation angle 10o. Radio antenna engineering rhombic antenna circuitry. Rhombic termination resistor termination resistor needs to be near 800. The antenna is placed end to end and terminated by a noninductive resistor to produce a unidirectional pattern. The leg lengths of the rhombic must be an integral number of half wavelengths. Diagram of radiation patterns of wire segments of a.
The sides of the rhombus each consist of two or more parallel conductors. This link is listed in our web site directory since thursday oct 26 2006, and till today rhombic antennas has been followed for a total of 2815 times. Rhombic antennas for television, october 1949 radio. If we assume othe average beamwidth of rhombic antenna as 10, then design an antenna system such that it will radiate maximum power over the. This antenna consists of four long wires, positioned in a diamond shape. The rhombic antenna is a broadband directional antenna. Rhombic antenna article about rhombic antenna by the free. It is arranged in the form of a rhombus or diamond shape and suspended.
The rhombics low cost, simplicity, reliability, and ease of construction sometimes outweighs performance. Exactly what i wanted to know, i may hold off on this one and search for a different type high gain uhf antenna. Rhombic antennas category is a curation of 14 web resources on, rhombic antennas for radio broacasting, rhombic antennas, rhombic antennas. This kind of antennas is well known thanks to their relative high gain associated to a simple design, being the main drawback the formation of important secondary lobes in the radiation pattern.
I have not kept in touch the last decade but bill was a mentor to me. Description and simulation of two types of rhombic antennas, using the software 4nec2. Antenna theory aperture an antenna with an aperture at the end can be termed as an aperture antenna. Each of the four sides is the same length about a quarterwavelength to one wavelength per section converging but not touching at an angle of about 42 at the fed end and at the far end.
The main feeder and the dissipation line are also centered at this point. This kit of parts for a rhombic antenna should be assembled by an experienced ham, or technician. Personally for me it was very interesting to read the book. The rhombic antenna is a directional wire antenna used on mf and hf bands for shortwave reception. A practical guide to the design of rhombic aerials. Rhombic antenna the highest development of the longwire antenna is the rhombic antenna it consists of four conductors joined to form a rhombus, or diamond shape. The directivity of a rhombic antenna can be reversed by interchanging the feeder and the terminal resistance. The most common use of a rhombic antenna is in amateur radio relay and broadcasting. Mutual coupling effects analysis in a crossrhombic antenna array. May 02, 2018 in this video, i have explained rhombic antenna by following outlines.
If we look at this link to this pdf document on rhombic design we find suggested dimensions for rhombic antennas. A rhombic antenna is made of four sections of wire suspended parallel to the ground in a diamond or rhombus shape. A rhombic antenna is made of four sections of wire suspended parallel to the ground in a. All resistors are carbon 5w, creating 10w max dissipation per leg. Rhombic antenna dimensions and plan for hf and vhf bands by n6jsx. Rhombic antennas suited to operation down as low as 2 mhz are large. It is organized in the form of a rhombus or diamond shape and suspended horizontally. I have worked him before and his signal is not just a result of a rhombic antenna, he runs a lot of wattage and has a lot of background noise too. It is usually used for high frequencies, which are also known as shortwave. Rhombic antenna works under the principle of travelling wave radiator. As i studied the arrl antenna handbook i learned about the various types of antennas. The cross rhombic antenna cra belongs to the family of traveling wave antennas, with circular polarization, medium gain, and a directional eld pattern. Oct 05, 2014 a rhombic antenna is a broadband directional wire antenna coinvented by edmond bruce and harald friis, in 1931, mostly commonly used in the high frequency hf or shortwave band. There are 2 versions of the rhombic antenna, the resonant rhombic antenna and the terminated rhombic antenna.
Rhombic antennas can be characterized as highpower, lowangle, highgain. The book contains just experience and needed information. Pdf mutual coupling effects analysis in a crossrhombic. The main category is rhombic antennas that is about rhombic antennas. It covers 174 mhz 192 mhz, centered around 168 mhz. Radiation angles vary with the design and ground coefficient. Rhombic antennas were the ultimate antenna design back in the golden age of wireless. Rhombic antennas, vbeam, and inverted v but, this was on 10 meters, not say 40. In this video, i have explained rhombic antenna by following outlines. However, building one required a large tract of land and a lot of telephone poles, because they have dimensions several times the wavelength, and back then the wavelengths in use were tens of meters and longer. The best of the wire type antennas is the rhombic antenna each side 4 of the rhombic antenna must be 1 or two wavelengths long. Antenna theory rhombic in antenna theory tutorial 25 february. The rhombic antenna is widely used for longdistance, highfrequency transmission and reception.
Such a double antenna consists of two rhombuses that are displaced with respect to each other by 0. Which if ive done this correctly means a wavelength of 1. Pdf we present an analysis of mutual coupling effects on radiation pattern and. Rhombic tv antennas unlike the conventional type of tv an tennas which use aluminum tubing and other material that can only be made in a modern factory, this type of antenna uses ordinary copper wire, insulators and poles, and is put up in much the same manner as the ordinary outside radio antenna which has been built by. The rhombic antenna is a highly directional array ideallysuited for medium to long haul circuits. The rgaa has numerous bent radiation elements, forming rhombic cells and loops. A rhombic antenna is a broadband directional wire antenna coinvented by edmond bruce and harald friis, in 1931, mostly commonly used in the high frequency hf or shortwave band. Bprh230 rhombic antennas have high directional gain and low takeoff angles and are best suited to long distance, point to point communications.
A typical rhombic antenna design would be at a height of between a half and a full wavelength. Rhombic antenna the rhombic antenna, usually used at receiver sites, is a unidirectional antenna. This kit of parts is not intended for novice antenna builders. I couldnt get excited by dipoles, loops, yagies, or quads because i wanted one antenna that would cover many bands and produce a strong signal. A rhombic antenna can be made of two obtuseangle v antennas that are placed side by side, erected in a horizontal plane, and terminated so the antenna is nonresonant and unidirectional. Explain resonant and nonresonant modes of long wire antenna. The antenna consists of a wire suspended above the ground in the shape of a rhombus, terminated at one end by a resistor equal the the wires characteristic impedance, about 400 to. Some years ago i became interested in a special type of antenna. Directional tactical wire antenna, designed for longrange pointtopoint communications. A rhombic antenna is a type of antenna that covers a wider range of frequencies than most antennae.
About rhombic antennas the resource is currently listed in in a single category. A rhombic grid array antenna rgaa is proposed and its frequencyscanning performance is discussed. The rhombic antenna is often claimed to be an exceptionally good antenna with very high gain. We will look at a few rhombic antenna designs including an inverted v in the article below. Advantages and liabilities of rhombic antennasedit. The rhombic antenna is an equilateral parallelogram shaped antenna. The rhombic antenna has for many years been a favorite for highfrequency skywave transmission and reception. Increased parallel resistor stages will increase overall input wattage. Rather than tiptoe up to trying to get in stations with rotators and larger and larger deep fringe antennas i found the rhombic antenna.
577 142 1173 1238 948 273 979 912 91 1131 1307 116 377 828 29 294 301 1372 1493 543 1204 1438 1527 28 1371 1238 883 1002 472 1341 498 1070 32 1005 1350 147