If you’re looking for a high-performing omnidirectional antenna, consider this design. It boasts 5 collinear radiant elements that are connected by phasing coils. The feed point is conveniently located at the base of the antenna on a J dipole. By adjusting the position of the feed point along the J, you can minimize the SWR. At the top end of the antenna, you’ll find a small loop that serves as a tie point, measuring just 1/2″ in diameter. The total length of the antenna is 295″. Each coil features 32 turns and has a diameter of 5/8″.
To accurately model this design, we should use simulation software that is capable of modeling curved wire segments and small, closely-spaced wires. With AN-SOF, you can use the “Helix” object to perfectly model each coil. By using only one segment per turn, this model demonstrates the efficiency of AN-SOF in simulating complex designs.