Terms & Conditions
Last Updated: September 2026
Important Notice: Measure Twice, Cut Once
All tools and calculators on AntennaCalcs.com provide theoretical mathematical starting points based on idealized free-space electromagnetic physics. Real-world antenna performance depends on physical surroundings, height above ground, earth conductivity, dielectric insulation, and build techniques.
1. Acceptance of Terms
By accessing and utilizing AntennaCalcs.com, you agree to be bound by these Terms and Conditions. If you do not agree with any part of these terms, you should not use our web tools.
2. Complete Limitation of Liability
To the maximum extent permitted by applicable law, AntennaCalcs.com, its operators, contributors, and authors shall not be held legally or financially liable for any damages, losses, expenses, or claims arising directly or indirectly from your use of this site. This includes, without limitation:
- Material Waste: Cutting expensive copper antenna wire, ladder line, coaxial cable, or aluminum tubing incorrectly based on calculated figures.
- Equipment Damage: Blown final output transistors, damaged power amplifiers, melted baluns/ununs, or damaged transceivers caused by excessive Standing Wave Ratio (high SWR) or impedance mismatches.
- Zoning & Regulatory Non-Compliance: Violations of local municipal building codes, homeowner association (HOA) covenants, deed restrictions, or tower/mast height and setback regulations.
- RF Exposure & Safety: Failure to comply with governing RF exposure guidelines (such as FCC OET Bulletin 65) or electromagnetic radiation limits.
- Physical Injury or Property Damage: Electrocution hazards from overhead power lines, structural collapse, falls from ladders/towers, or lightning strikes during the assembly, erection, or testing of antennas.
3. Mandatory Engineering Best Practices
Every seasoned radio operator knows that calculators yield initial figures, not final bench truths. When using our dimensions, you agree to observe standard RF construction safety:
Always cut long: Add 3 to 6 inches (8 to 15 cm) to wire antenna elements to allow for end-insulator loops and progressive pruning.
Test at low power: Verify SWR curves using an antenna analyzer or NanoVNA before transmitting high RF power into a newly built system.
Inspect overhead lines: Never construct, raise, or adjust an antenna within falling distance of electrical power wires.
Account for ground & height: Resonant frequencies and feedpoint impedances shift as antenna height above ground varies.
4. "As-Is" Mathematical Models
The formulas provided on this site are derived from established amateur radio literature (including ARRL publications, Cebik NEC regressions, and standard electromagnetic equations). While we test all calculators thoroughly, services and algorithms are provided "AS IS" and "AS AVAILABLE" without warranty of any kind, express or implied.