diddy-boy / OFFgrid-SDR

# OFFgrid-SDR
**A complete radio receiver in a single file. No installation, no internet, no account: plug in an RTL-SDR stick, open the page, and listen.**
OFFgrid-SDR is a full software-defined radio receiver that runs entirely in your web browser from one file. Put the `index.html` on a USB pen drive with an RTL-SDR stick and an antenna, and you have a working shortwave, FM, airband and VHF/UHF receiver on almost any computer: no software to install, no administrator rights, no drivers to download on site (on most systems), and nothing that ever needs an internet connection.
## Demo video (version 1.1)
Look good on a Chromebook in tent mode or tablet mode
## Why I made this
The humble RTL-SDR stick needs some love. It has always been treated as an add-on: a cheap way into other SDR software, never the star of the show. I decided to change that, and build a receiver made for the RTL-SDR, that anyone can carry on a pen drive and use anywhere.
Ideally, I wanted to see a whole 10 MHz of spectrum in one go, spot a signal, and click on it.
From there, the workflow goes:
1. **Click a signal** in the 10 MHz overview. The view switches to a 2.04 MHz wide bandwidth with a waterfall.
2. **Zoom in, or pause** and highlight a signal in the waterfall. A zoomed-in replay section appears.
3. **Use the A/B buttons** to narrow the selection in more detail.
4. **Save the signal** for later analysis.
So in a few steps I can go from a 10 MHz wide view down to a signal possibly only tens of hertz wide, with the signal of interest saved for later use.
**10 MHz view → 2.04 MHz view → signals tens of Hz wide → analyse or save**
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## What's new in 1.6
**A cleaner, simpler layout**
- **Top bar:** frequency, S-meter, mode, volume, mute, record, settings and help are always visible, on desktop and on phones.
- **One-click mode buttons:** **AUTO · FM · AM · SAM · USB · LSB · CW · More ▾**. SAM-U, SAM-L, the decoders and Wide/Narrow FM are under **More**.
- **Settings dialog:** receiver settings open from the gear icon, with tabs for **Device, Display & tuning, Audio & recording, Decoders, Calibration and Backup**.
- **No duplicate controls:** mode, filter width and step each have one control.
- **Status lights** under the frequency digits, and a larger S-meter reading that balances the frequency.
- **Layout stability:** the Alerts button no longer shifts the spectrum toolbar, and the top bar no longer jumps in height on shortwave or when a frequency label appears.
- **Scrolling status line:** a message too long for its space scrolls instead of being cut off (with "reduce motion" on, it's shortened and the whole message is on hover).
- **Seek / Step box pinned:** it stays at the top of the side panel while the panels below scroll.
- **Panels menu** in the Seek / Step box: jump straight to Band, Memories, Audio & gain and the rest. The zoom buttons are now **−**, **+** and the zoom level (click it for the full view).
- **Tall (portrait) view:** on a Chromebook or tablet he