ewcalc — EW Engineering Calculator

A multi-platform electronic warfare engineering calculator covering antenna analysis, RF propagation, link budgets, receiver performance, communications and radar jamming, emitter location, radar (range equation, detection statistics, Doppler & resolution), and spread-spectrum communications — implementing the standard formulas, inspired by and audited against the EW101 series by David Adamy.

Getting ewcalc

Pre-built artifacts for all three platforms are attached to each GitHub Release:

Platform	Artifact	Notes
Windows	.msix	Unsigned by default; see frontend/windows/ewcalc-winui/README.md for sideloading a self-signed cert
macOS	.dmg	Signed and notarized — opens directly, no Gatekeeper prompt
Linux	.AppImage	chmod +x, then run directly; no installation required

To build from source instead, see Building below.

Architecture

Layered, with clean separation:

• libew — pure C++20 calculation library, no UI, no external dependencies
• ewpresenter — platform-agnostic presenter/viewmodel layer
• bridge/ — plain-C API over ewpresenter, used by the macOS Swift frontend (Swift cannot import C++ directly); Linux and Windows link ewpresenter directly
• frontend/ — platform-native UIs: WinUI 3 (Windows), SwiftUI (macOS), Qt6 (Linux)

Layer and frontend detail: docs/ARCHITECTURE.md.

libew modules

Module	Content
core	Strong-type units (Dbm, Db, Km, Mhz, Kelvin, …), constants
propagation	FSPL, 2-ray ground reflection, Fresnel zone, knife-edge diffraction, earth bulge, radar horizon range
antenna	ERP, gain conversions, beamwidth
link	One-way link budget, effective range
receiver	Sensitivity, cascaded NF (Friis), SFDR, digital DR and SQNR, noise temperature conversions
jamming	Comms J/S ratio, burnthrough range, partial-band optimization; radar self-protection and stand-off J/S and burnthrough range
location	CEP from AOA bearing error, TDOA timing error, and EEP
radar	Radar range equation, pulse compression, coherent integration gain, LPI advantage; detection statistics (Albersheim, Shnidman with Swerling 0–4, fluctuation loss, dwell/hits per scan, false-alarm rate); Doppler shift, unambiguous range/velocity, blind speed, range and cross-range resolution
digital	Eb/N₀ ↔ SNR conversion (both directions), DSSS process gain, jamming margin, required J/S

ewpresenter

Eleven presenters wrap the libew modules for use by any view layer:

Presenter	Inputs	Key outputs
PropagationPresenter	distance, frequency, antenna heights, obstruction height	FSPL, 2-ray loss, Fresnel zone, regime, earth bulge, radar horizon, knife-edge diffraction loss
AntennaPresenter	gain, az/el beamwidth, Tx power, frequency	ERP, beamwidth from gain, gain from beamwidth, wavelength
LinkPresenter	Tx power/gain, Rx gain, geometry, sensitivity	Received power, link margin, effective range
ReceiverPresenter	Bandwidth, NF, SNR, stage chain, ADC bits	Sensitivity, cascaded NF, system noise temp, SFDR, digital DR, SQNR
JammingPresenter	Signal/jammer ERP, geometry, frequency, J/S threshold	J/S ratio, burnthrough range, partial-band optimum BW (N/A when hop range = 0 or J/S is below the threshold)
RadarJammingPresenter	Geometry (self-protection / stand-off), radar and jammer ERP, RCS, target range, J/S threshold; stand-off jammer range and mainbeam/sidelobe gains	J/S ratio, J/S margin, burnthrough range, status
LocationPresenter	Bearing error, range, TDOA timing error, EEP semi-axes	CEP (AOA, TDOA, and EEP methods)
RadarPresenter	Tx power, gain, RCS, frequency, NF, TB product	Max range, two-way loss, PC gain, coherent integration gain, LPI advantage
DetectionPresenter	Pd, Pfa exponent, pulses, Swerling case, beamwidth, scan rate, PRF, bandwidth	Required SNR (Shnidman and Albersheim), fluctuation loss, dwell time, hits per scan, false-alarm rate
DopplerPresenter	Frequency, radial speed, PRF, bandwidth, range, az/el beamwidths	Doppler shift, unambiguous range/velocity, blind speed, range and cross-range resolution
DigitalPresenter	SNR, bandwidth, data rate, chip rate, required Eb/N₀, impl. loss	Eb/N₀, SNR from Eb/N₀, DSSS process gain, jamming margin, required J/S

Each presenter validates inputs, calls libew, and fires a std::function callback with formatted output strings. No platform types are exposed.

A console harness (ewpresenter_harness) exercises all presenters against default inputs.

Building

Requires CMake ≥ 3.25 and a C++20 compiler. See AGENTS.md for per-platform toolchain prerequisites (Xcode, Qt6, Visual Studio, etc.).

Core libraries and tests

cmake -B build
cmake --build build --config Release
ctest --test-dir build -C Release --output-on-failure

To run the presenter harness:

build/bin/Release/ewpresenter_harness

Platform frontends

Platform build scripts are in scripts/. Each builds the native libs then the frontend, and accepts --config Debug|Release and (on Linux/macOS) --package to produce a distributable artifact.

Platform	Script	Package output
Windows	scripts/build-windows.ps1	unsigned .msix (-Sign for signed)
macOS	scripts/build-macos.sh	signed + notarized .dmg
Linux	scripts/build-linux.sh	.AppImage

macOS packaging requires a Developer ID Application certificate in the keychain and xcrun notarytool credentials stored under the ewcalc-notarytool profile.

Formula reference

See docs/formulas.md for the equations, units, assumptions, and references behind each calculator output.

API documentation

libew and ewpresenter headers use Doxygen-style /// comments. Build the HTML API reference locally with:

doxygen Doxyfile

Output lands in docs/html/index.html. CI runs the same command on every push and pull request and publishes docs/html/ as a workflow artifact; it does not publish to GitHub Pages yet (a reasonable future enhancement).

Contributing

See CONTRIBUTING.md for the branch/PR workflow, build and test instructions, and code style. See CHANGELOG.md for release history. Found a security issue? See SECURITY.md for how to report it privately.

Current status

All three platform frontends — Windows (WinUI 3), macOS (SwiftUI), and Linux (Qt6 Widgets) — are feature-complete across all eleven calculators plus a thirteen-page reference library (glossary, units, frequency bands, and a formulas-and-tables page per calculator domain), with collapsible geometry-diagram sections on seven of the calculator panes. See CHANGELOG.md for release history.

License

MIT — see LICENSE.