# EMF Spectrum Explorer — product brief

> Educational interactive chart of radio frequency allocations worldwide: national tables, FCC (US), CEPT ECA, and ITU Regions 1–3.

## What it is

EMF Spectrum Explorer helps people understand which radio services are allocated where in the spectrum. It presents a giant horizontal, logarithmically scaled chart (approximately 8.3 kHz through 3 THz). Users choose a country or administration, filter by service category, search for everyday uses or frequencies, and open a band for primary/secondary allocation details.

The product is inspired by the classic NTIA United States frequency allocation wall chart. It is installable as a Progressive Web App and works offline after the first visit.

This is an educational visualization. It is not an official regulatory source. For operational or legal decisions, consult the relevant national administration, the FCC table, or the ITU Radio Regulations.

## Coverage and data

| View | Dataset | Notes |
| --- | --- | --- |
| United States | FCC Online Table of Frequency Allocations (47 CFR § 2.106) | National US table |
| National administrations | Bundled domestic tables (dozens of countries) | e.g. Ofcom, BNetzA, ANFR, ISED, ACMA, MIC, Anatel, IFT — see `docs/data-sources.md` |
| Other countries | ITU RR 2024 Art. 5 by region | Fallback when no national table is bundled |
| ITU Region 1 | Europe, Africa, Middle East, CIS | Regional baseline |
| ITU Region 2 | Americas | Regional baseline |
| ITU Region 3 | Asia-Pacific | Regional baseline |
| CEPT ECA | European Common Allocation | Regions tab (not a national table) |

Service colors follow NTIA chart conventions. Color-vision-friendly palettes and optional hatch patterns are available in the UI.

## Primary interactions

1. Pick a country, region, or use the world map picker (optional “national tables only” filter).
2. Scroll the log-scale spectrum; use zoom for denser HF regions.
3. Toggle service categories in the legend to dim non-matching bands.
4. Search (command palette) for uses, countries, or jump to a frequency such as `915 MHz`.
5. Click a band for allocation details.
6. Optionally expand to a full electromagnetic spectrum context view, or split service categories onto separate tracks.

Deep links keep locale in the path and selection/frequency in the query string, for example `/fr?country=FR&hz=2.4GHz` or `/?region=ITU-R1&hz=915MHz`.

## Languages

UI chrome: English, Chinese (Simplified), Hindi, Spanish, Arabic (RTL), French, Bengali, Portuguese, Russian, Indonesian.

Locale URLs use a path prefix (`/es`, `/zh`, …); English is `/`. Deep links use `?country=` (administrations), `?region=` (ITU R1–R3, FCC, ECA), and `?hz=` (e.g. `915MHz`).

## Technical stack

Vite, React, TypeScript, Tailwind CSS v4, D3 (log frequency scale), vite-plugin-pwa for installability and offline caching.

## Source and license context

- Repository: https://github.com/jamesrobinson50/radio-spectrum
- Bundled allocation JSON lives under `src/data/allocations/` in the repository.
- Dataset registry and attribution: `docs/data-sources.md`
- Always prefer primary regulatory texts over this app for compliance.

## Site files for machines

- `/llms.txt` — curated index for language models
- `/robots.txt` — crawler allow rules
- `/sitemap.xml` — URL inventory (when deployed with `VITE_SITE_URL`)
- `/og-image.jpg` — 1200×630 social preview image
- `/manifest.webmanifest` — PWA manifest (generated at build)