What Can I Pick Up?

amfm.cc — find which AM/FM radio stations you should be able to receive at a given location, based on real FCC license data and physical propagation models.

Click a spot on the map (or search a location, or use your device's GPS), and the app shows every station whose signal should reach you above a threshold you control, with AM and FM plotted separately and a reception-strength slider from "fringe" to "strong / city-grade."

How it works

• Station data comes from the FCC's own license databases: LMS (current filings) and CDBS (the legacy system LMS replaced in 2014). Roughly 54% of licensed AM stations and 29% of licensed FM stations haven't been re-filed since the LMS migration, so this app backfills those from CDBS using facility_id, a stable identifier across both systems.
• FM reception is modeled as free-space field strength with a radio-horizon cutoff based on antenna height (HAAT).
• AM reception uses the FCC's own published groundwave curves (47 CFR 73.184/73.190, "Graphs 1-20") — the actual regulatory basis for AM groundwave range, digitized directly from the FCC's PDFs — rather than a generic formula, since AM groundwave propagation doesn't have one.
• Both models assume flat terrain, average ground conductivity, and no obstructions — see the in-app disclaimer for what's intentionally left out (terrain, directional antennas, AM nighttime skywave).

Station data is rebuilt weekly by a GitHub Actions workflow that pulls fresh FCC data, joins it, and partitions it into small per-region files the frontend fetches on demand as you pan around.

Running it locally

This is a static site with no build step — gh-pages is the deployed site. Clone the repo and serve the directory with any static file server, e.g.:

python -m http.server 8000

then open http://localhost:8000.

Repo layout

• index.html, css/, js/ — the frontend (vanilla JS, Leaflet for the map)
• scripts/ — Python pipeline that fetches FCC data and builds data/plus4/*.json (regenerated weekly; don't hand-edit)
• .github/workflows/ — the scheduled data-refresh workflow

See CLAUDE.md for the deeper infra/data notes (why certain FCC hosts need special handling, known data gaps, reference stations used for regression-checking changes, etc).