Apps / Antenna design helper
What antenna will fit?
Pick the bands you want and tell it how much room you have. It suggests antennas that fit, with cut lengths and how to feed them. Once it is up, the second half tells you how much to trim from your analyzer readings.
1. Your bands and your space
Everything here is saved in this browser only.
Clear distance between the two farthest supports.
Tree, mast or roofline you can get a rope over.
Defaults to the middle of your lowest band.
Antennas for that space
Lengths use the usual wire formulas (468 ÷ MHz for a half wave, 234 ÷ MHz for a quarter wave, 1005 ÷ MHz for a full-wave loop). Real antennas vary with wire, insulation, height and what is nearby, so cut a little long and trim. Harmonic bands tend to land slightly high in practice; a tuner covers the gap.
2. Tune it from your analyzer
Put the antenna up, find where the SWR (standing wave ratio) is lowest, then enter that frequency below — or load the file your analyzer exports.
For a vertical, the radiating element only.
Filled in for you if you load a file.
Touchstone (.s1p) from a NanoVNA and similar, or a CSV with frequency and SWR
(or frequency, R and X) columns.