The design point: Pattern distortion is a change in lobe direction, strength, polarization, or null depth caused by conductors, ground, terrain, supports, feed lines, or unequal current paths near the antenna.
Why the complete system matters
Objects can reradiate coupled current, block or reflect fields, and change feed-point current at the same time. The result is three-dimensional and frequency-specific.
The assumption that breaks it
A normal SWR does not prove that the intended pattern survived, and a visually straight antenna can still couple strongly to nearby metal.
Build or deploy it correctly
Map conductive surroundings, preserve clearance and symmetry, control common mode, compare exact-installation models or field bearings, and treat pattern data from another geometry as non-transferable.
Configuration boundary
Use the exact product guide, electrical topology, geometry, materials, loading, feed, return path, support, and environment. Mechanical fit or a visually similar arrangement does not establish electrical equivalence.
