ALYX ANTENNA GUIDE
RHOMBIC ANTENNA FOR SHORTWAVE RADIO BROADCASTING

 
GENERAL DESCRIPTION

photo rhombic antenna

The rhombic antenna is a diamond-shaped antenna, suspended between 4 masts.

The 3 parameters of a rhombic antenna are:
- l : antenna leg length
- g : one half of the large interior angle
- h : antenna height

All legs of the antenna are the same length, and opposite angles of the diamond are equal.

The leg lengths of the rhombic must be an integral number of half wavelengths.

A typical rhombic antenna design would be at a height of between a half and a full wavelength.

There are 2 versions of the rhombic antenna, the resonant rhombic antenna and the terminated rhombic antenna.

The resonant rhombic antenna is bidirectional, while the terminated rhombic antenna is unidirectional.

A considerable amount of power may be lost in the terminating resistance and represents the price that has to be paid for some desirable features such as simplicity of construction, relatively wide bandwith of operation and high directivity gain.
 
TYPICAL RADIATION PATTERNS
Azimuth pattern Elevation pattern
typical azimuth pattern rhombic antenna typical elevation pattern rhombic antenna

 
TYPICAL COVERAGE MAP

typical coverage map rhombic antenna


TECHNICAL SPECIFICATIONS
ELECTRICAL
Azimuth pattern directional
Frequency ranges 5-35 MHz
Gain 9 dBi
Input impedance 600-800 ohm balanced
Polarization horizontal
Power ratings up to 100 kW average
VSWR 2.5 : 1 or less
DIMENSIONS
Length
Width
Height
Specifications may change without notice
THIS TYPE OF ANTENNA IS AVAILABLE FROM
Manufacturer Type number Power Level

 
ABBREVIATIONS
Abbreviation Explanation
Power Level L low 1-5 kW
M medium 10-50 kW
H high 100-500 kW