Calculator - Full-Wave Wire Loop
Full-Wave Horizontal Wire Loop
A full-wave loop can require a lot of territory, and needs at least several tall supporting structures (trees, towers, etc.) However on the right property, it is an effective, low-noise, omnidirectional antenna.
The loop provides about 2dB of gain when hung in a square shape, but more if the shape of the antenna can be expanded to maximize interior space. Though impractical to hang, a true circle shape would provide nearly 1dB of gain over a square shape.
Theoretical impedance of the loop is 100 ohms, so it should be fed with a matching system designed to lower impedance closer to the 50 ohms of typical coaxial feedlines. One method involves a matching section of 75-ohm coax, carefully-cut so that it matches the dimension provided below after connections have been made. The dimension is calculated using the velocity factor of the 75-ohm coax used.
Enter the frequency of interest below. The dividend factor typically used for calculating full-wave loops is 1005, but it can be adjusted below if desired. The velocity factor input should be correct if the 75-ohm matching stub results will be used.