SKYWAVE

A "TV Guide for shortwave." One HTML file that tells you what's on the air right now — broadcast stations, ham nets, and propagation — and keeps working with no signal bars and no build step.

→ Live app: cdburgess75.github.io/SkyWave ←

  

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Overview

Shortwave listening has a discovery problem: thousands of broadcasts rotate through the day on schedules buried in a 12,000-row CSV, and the usual answer is desktop software or a stack of printed guides. SKYWAVE turns that schedule into a live, filterable "what's on right now" view that runs on the device already in your pocket — including in the field, with no connectivity.

Problems it solves

• "What can I hear at this hour?" — the On Air view filters the full EiBi schedule down to broadcasts transmitting this minute, day-of-week aware, sorted by frequency.
• "Who is that on 9.420?" — type a dial frequency, get every scheduled match within ± tolerance, on-air entries first.
• "Is anyone running a net?" — live ham nets in session via NetLogger, plus the major scheduled HF nets built in.
• "Which band should I try?" — grayline timing and band-by-band advice computed on-device from your coordinates, plus live K-index.

Why it stands out

	SKYWAVE	Typical alternatives
Install	Open a URL, add to home screen	Desktop app or paper guide
Offline	Everything except live feeds works in airplane mode	Usually online-only
Footprint	One ~90 KB HTML file, zero runtime dependencies	Multi-megabyte apps
Privacy	No account, no tracking, no server — data stays on-device	Varies
Build step	None. index.html is the app	Bundlers, frameworks

Key Features

Feature	Detail
📻 On Air Now	Live view of the EiBi schedule; chips for favorites/language, band + free-text filters, 30 s auto-refresh
🔍 Search / By Freq	Full-text search across 12k+ entries; dial-frequency identification with ±2/5/10 kHz tolerance
📡 Nets (default view)	Live nets in session (NetLogger API) + 15 built-in national & Southeast-US HF nets (traffic nets for LA/MS/AL/GA/TN/SC/FL, SouthCARS, Waterway, Maritime Mobile, Hurricane Watch…) — offline and on-air aware
★ Favorites	Star any listing; ✓ "heard today" strikethrough that clears at 0000 UTC
📝 My Frequencies	Your own nets/channels merged into every view
🌅 Grayline planner	Sunrise/sunset/solar-noon + band advice from an on-device solar algorithm — no network
📶 Propagation	HamQSL solar widget, live NOAA K-index with 8-period trend
🛠 Field tools	Antenna calculator (dipole/vertical/loop), band-card export, print sheet, kiosk mode with wake-lock
🎛 UX	LED dark/light themes, font scaling, Maidenhead grid in header, first-run location wizard, UTC + local clocks
📴 PWA	Service worker + manifest; installs standalone, updates itself, EiBi schedule cached in localStorage

Architecture

SkyWave/
├── index.html              ← the entire application (HTML + CSS + JS, "use strict")
├── sw.js                   ← service worker: cache-first shell, background refresh
├── manifest.webmanifest    ← PWA install manifest
├── icons/                  ← SVG + PNG app icons
├── test/
│   └── smoke.mjs           ← Node + jsdom smoke harness (3 checks)
├── docs/
│   ├── GUIDE.md            ← user guide: install + every tab, plain English
│   ├── ARCHITECTURE.md     ← data pipeline, rendering model, algorithms
│   ├── DATA_SOURCES.md     ← external API contracts (EiBi, NetLogger, NOAA, HamQSL)
│   └── screenshot-*.png
├── HANDOFF.md              ← full engineering handoff: conventions, storage schema, roadmap
└── CHANGELOG.md            ← CalVer (YYYY.MM.DD) history

Core data flow — one array, one renderer:

buildBase()  =  TIME stations + built-in nets + user frequencies      (always present)
EIBI[]       =  parsed EiBi CSV                                       (cached / fetched)
DATA         =  buildBase().concat(EIBI)     ← single source of truth

Design rules enforced throughout: no runtime dependencies, every localStorage access wrapped in try/catch, all dynamic rows use event delegation via data-act attributes, all network features cache their last result and render an explicit offline state. See docs/ARCHITECTURE.md.

Getting Started

Prerequisites

• Users: any modern browser. That's it — no account, no API keys.
• Developers: Node ≥ 18 (only for the test harness) and any static file server.

Install as an app (recommended)

1. Open cdburgess75.github.io/SkyWave in Safari (iOS) or Chrome (Android/desktop) — not an in-app webview, which blocks fetch
2. Share → Add to Home Screen (iOS) or Install app (Chrome)
3. Launch from the home screen; on first run a 3-step wizard asks for your location (GPS or manual) to power grayline and grid-square features
4. Tap ⟳ Update now on the Ref tab once while online to pull the full EiBi schedule — it's stored offline from then on

Run locally

git clone https://github.com/cdburgess75/SkyWave.git
cd SkyWave
python3 -m http.server 8000    # any static server works
# open http://localhost:8000

Opening index.html directly from disk also works for everything except the service worker.

Usage

New here? The full User Guide walks through install and every tab in plain English. The table below is the quick reference.

I want to…	Do this
See what's broadcasting now	Listen → On Air — filter by band, language, or text
Identify a signal on the dial	Listen → By Freq — type 9420 or 9.420
Find active ham nets	Open the app — Nets is the default view: live list on top, scheduled majors below
Keep a station	Tap ★ on any row; find it under Saved
Mark a catch	Tap ✓ on a favorite — struck through until 0000 UTC
Plan a band opening	Tools → Grayline — band advice for your location
Cut an antenna	Tools → Antenna calculator — enter MHz or kHz
Update the schedule	Ref → ⟳ Update now (auto-updates on launch when stale)

Run the test suite

npm install -D jsdom   # one-time
node test/smoke.mjs

Three checks must pass: script syntax, getElementById ↔ HTML id coverage, and a full jsdom boot.

Contributing

Small, focused PRs are welcome. Ground rules (full detail in HANDOFF.md):

• Keep it one file. No frameworks, no build step, no runtime dependencies.
• Offline-first is the contract. A network feature must cache its last result and render a sensible offline/failed state.
• Escape everything rendered from data (esc() for text, attr() for attributes).
• Run node test/smoke.mjs before pushing — all three checks green.
• Version bumps are CalVer (YYYY.MM.DD) in index.html and sw.js cache name, with a CHANGELOG.md entry.

Operating-side features (QSO logging, POTA/SOTA spots, ADIF export) are out of scope — SKYWAVE is a listening guide, not a logger.

Data Sources & Credits

Source	Used for	Terms
EiBi © Eike Bierwirth	Broadcast schedule	Free to copy & distribute, attribute EiBi
NetLogger	Live nets in session	Fetched only on demand
NOAA SWPC	Planetary K-index	Public API
HamQSL N0NBH/K4HG	Solar conditions	Linked & credited

License

Code is MIT. Schedule data remains © EiBi under its own terms — do not relicense the data.

_{Built for offline field use · All times UTC · 73}