The “KING of Wire Antennas is a Rhombic”

Most of our group here on the KA9QJG Repeater know that I am Fascinated with antennas, I build them whenever I Have time to do so, some of them work and some do not.

A couple of weeks ago I made a 220 MHz 3 element yagi with a direct feed 50 Ohm coax, it worked great.

I use a free antenna modeling software called MMANA-GAl Basic 

Yesterday I was talking to a friend of mine HZ1ZH about antennas, he asked me about the best antenna, I told him that in my opinion, the rhombic antenna is the king of antennas, it is used in broadcasting, Amateur radio & Military, it has tremendous gain and can be used for all amateur radio bands from 160 meters to 6 meters if cut the rite lengths.

It also can be made for the VHF/UHF Bands.

Here is a brief description of the Rhombic that I gathered from the WW Web.

Rhombic antenna is made of four Length’s of wire suspended parallel to the ground in a diamond shape.  converging but not touching at an angle of about 42° at the fed end and at the far end. The length is not critical, typically from one to two wavelengths, but there is an optimum angle for any given length and frequency. A horizontal rhombic antenna radiates horizontally polarized radio waves at a low elevation angle off the pointy ends of the antenna.

If the sections are joined by a resistor at either of the pointy ends, then the antenna will receive from and transmit to only the direction the end with the resistor points at. The primary purpose of the terminating impedance of the rhombic antenna is to produce a sharp, unidirectional radiation pattern. For low-power (up to 1 KW) transmission, the termination impedance is usually a 600-800 ohm noninductive carbon resistor. Its principal advantages over other types of antenna are its simplicity, high forward gain, wide bandwidth, and the ability to operate over a wide range of frequencies.

And here are the results of the antenna modeling software MMANA-GAL, Testing From 160- 6 Meters Amature radio bands.

One last word…… this antenna is too large for practical amateur use, but if you have the property it can be done with ease.

And Here Are The Calculation For The Frequencies.

Take a Look At The Foot Print Of This Size Of a Rhombic If Installed At My Home QTH.

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2 thoughts on “The Legendary Rhombic Antenna”
  1. Ayman,
    Sometimes I miss what is right in front of me… Help me out with where the dimensions are shown in the MMANA-GAL software. I’ve taken a whack at this software and would like to learn more.
    Would you consider firing up the camera the for the next antenna simulation? Just have it looking at the screen and talk through what you are doing and what your considerations are. It would be a great resource for us to watch and use as a reference.
    Thanks for posting this and developing this website. Your efforts are greatly appreciated.
    John

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