Verticals and mobile antennas

Vertical antennas trade the dipole’s figure-eight for omnidirectional coverage and a low radiation angle — good for distant contacts and mobile use.

Working against ground

A quarter-wave monopole needs a ground to mirror its missing half. On a tower or roof a ground-plane antenna supplies that with radials; on a vehicle the body does the job for a whip.

Squeezing out more

A 5/8-wave vertical raises the current distribution to push more energy toward the horizon, giving a few dB over a quarter-wave — a favourite for VHF mobile.

Trade-offs

Verticals are compact and great for omnidirectional and low-angle work, but they need a decent ground system and tend to pick up more man-made noise than a horizontal wire up high.