Free RF calculators that show their work
Waveshed now has a tools section with free RF calculators. They run in your browser, draw what they compute, and show the formula, a worked example and the sources behind every number. There is no account and nothing to install, and every tool speaks English, German and French.
What is in the collection?
The collection launches with fifteen tools and covers the questions that come up around every link plan.
- Link planning: Free-space path loss calculator, Fresnel zone calculator, Radio horizon calculator, Earth bulge calculator, Link budget calculator, LoRa airtime calculator, Satellite look angle calculator, Knife-edge diffraction calculator, LoRa / Meshtastic range calculator, Walkie-talkie range calculator
- Units & spectrum: dBm ↔ watt converter, Frequency ↔ wavelength calculator, Wi-Fi channel to frequency converter, Field strength converter
- Transmitter & feedline: EIRP calculator, VSWR calculator, Coax cable loss calculator, Attenuator pad calculator, Skin depth calculator, RF exposure distance calculator
- Antennas: Antenna downtilt calculator, Dipole length calculator, Parabolic dish gain calculator, Antenna beamwidth ↔ gain calculator, Quarter-wave vertical calculator
- Signal & noise: Noise floor calculator, Doppler shift calculator
- Hiking & outdoor: How far can you see? Horizon distance calculator, Distance & bearing calculator, Horizon mask calculator (ridge elevation angle)
Why does every calculator show its formula?
Most online calculators hand you a number and stop. We think the number is the least interesting part. Each Waveshed tool therefore explains how it computes, sets its formula in proper notation, walks through a worked example you can check by hand, and cites the standards it rests on, from ITU-R recommendations to FCC and ETSI texts. The diagrams react to your inputs, so you see what a change does instead of guessing.
The coverage simulator follows the same principle. A result you cannot check is a result you cannot trust.
Where do formulas end and the map begins?
Formulas assume flat, empty space. Real links cross ridges, forests and rooftops, and that is what the coverage simulator is for. The tools give you the first estimate in seconds, and the simulator drapes it over real terrain. The Fresnel zone calculator tells you how much clearance a link needs, and the elevation profile in the simulator shows whether your terrain provides it.
What comes next?
The collection is a starting point, not a finish line. High on the list are a LoRa airtime calculator, parabolic dish gain, satellite look angles, knife-edge diffraction and a field-strength converter, plus a radar cluster around the radar range equation, the radar horizon and PRF limits.
We will also spotlight tools here on the blog from time to time. One tool per post, with the story behind its number. Why 60% of a Fresnel zone must stay clear. What a VSWR of 2:1 really costs. Why 2.4 GHz Wi-Fi has three usable channels in the US and four in Europe. If a calculator leaves you with a question, that question is a good candidate for the next post.
Missing a tool you need? Tell us. The list of candidates is long, and requests move tools up it.
FAQ
- Are the RF calculators free?
- Yes. All of them run entirely in your browser, without an account. That will not change, and it matches the simulator itself, which is free for line-of-sight and RF coverage runs.
- Do the tools work on phones and in other languages?
- Yes. Every tool is built for mobile and desktop and ships fully translated in English, German and French, including the diagrams and their captions.
- Will more calculators be added?
- Yes, steadily. Radar tools, LoRa airtime and satellite look angles are next in line, and the blog will announce notable additions. Suggestions are welcome through the contact page.
The whole collection lives at waveshed.io/tools. Bookmark the ones you use. The URLs are stable and every tool stands on its own.