Practical Stacked Dipole Planning
A stacked dipole array uses two or more dipoles on one support. Each element works on the same frequency. The array shapes radiation by spacing elements and feeding them in phase. Good planning reduces trimming time. It also helps you choose safe support height, feed line routing, and matching parts before parts are cut.
Why Stacking Helps
A single half wave dipole has useful broadside gain. Stacking adds more capture area. When elements are spaced well, energy combines in the main direction. The main lobe becomes stronger. Some high angle energy is reduced. This can help long distance work, repeater links, weak signal listening, and field testing. The exact pattern still depends on height, ground, nearby metal, and feed accuracy.
Key Measurements
Frequency sets wavelength. Wavelength then sets total dipole length and spacing. A normal dipole is close to one half wavelength overall. Real wire is usually shorter because of end effect and velocity factor. Tubing, insulation, and supports can change the final cut. The calculator includes a trim setting so the first cut can be conservative. Many builders cut slightly long. Then they trim both ends equally during tuning.
Feeding the Stack
Equal phase feeding is important. In phase lines make each dipole current rise and fall together. Parallel feeding lowers impedance as more elements are joined. Series feeding raises impedance. A quarter wave transformer can move the array impedance toward the coax value. The output is an estimate, not a network analyzer reading. Use it to select a starting layout.
Interpreting Results
The gain result assumes good phasing and a practical efficiency value. Real gain may be lower from conductor loss, mismatch, feed line loss, and imperfect spacing. Stack height shows the distance from the first dipole to the last dipole. Add end clearance and mast clearance when building. Use the SWR estimate only as a quick mismatch guide.
Build Notes
Keep elements straight and parallel. Use the same wire length for every dipole. Keep feed branches balanced. Weatherproof outdoor junctions. Record the final tuned length. Saved notes help repairs and future arrays. Use local safety rules. Keep the antenna away from power lines. Check hardware after storms and before each portable session always.