openwebrx/README.md

OpenWebRX
=========

OpenWebRX is a multi-user SDR receiver software with a web interface.

![OpenWebRX](/screenshot.png?raw=true)

It has the following features:

- <a href="https://github.com/simonyiszk/csdr">libcsdr</a> based demodulators (AM/FM/SSB),
- filter passband can be set from GUI,
- waterfall display can be shifted back in time,
- it extensively uses HTML5 features like WebSocket, Web Audio API, and &lt;canvas&gt;.
- it works in Google Chrome, Chromium (above version 37) and Mozilla Firefox (above version 28),
- currently only supports RTL-SDR, but other SDR hardware may be easily added.

**News:**
- My BSc. thesis written on OpenWebRX is <a href="http://openwebrx.org/bsc-thesis.pdf">available here.</a>
- Several bugs were fixed to improve reliability and stability.
- OpenWebRX now supports compression of audio and waterfall stream, so the required network uplink bandwidth has been decreased from 2 Mbit/s to about 200 kbit/s per client! (Measured with the default settings. It is also dependent on `fft_size`.)
- OpenWebRX now uses <a href="https://github.com/simonyiszk/csdr#sdrjs">sdr.js</a> (*libcsdr* compiled to JavaScript) for some client-side DSP tasks. 
- Auto-update capability for *sdr.hu* added (currently only *sdr.hu* beta testers can use it).
- License for OpenWebRX is now Affero GPL v3. 

## Setup

OpenWebRX currently requires Linux and python 2.7 to run. 

First you will need to install the dependencies:

- <a href="https://github.com/simonyiszk/csdr">libcsdr</a>
- <a href="http://sdr.osmocom.org/trac/wiki/rtl-sdr">rtl-sdr</a>

After cloning this repository and connecting an RTL-SDR dongle to your computer, you can run the server:

	python openwebrx.py

You can now open the GUI at <a href="http://localhost:8073">http://localhost:8073</a>.

Please note that the server is also listening on the following ports (on localhost only):

- port 8888 for the I/Q source,
- port 4951 for the multi-user I/Q server.

Now the next step is to customize the parameters of your server in `config_webrx.py`.

Actually, if you do something cool with OpenWebRX (or just have a problem), please drop me a mail:  
*Andras Retzler, HA7ILM &lt;randras@sdr.hu&gt;*

## Usage tips

You can zoom the waterfall display by the mouse wheel. You can also drag the waterfall to pan across it.

The filter envelope can be dragged at its ends and moved around to set the passband.

However, if you hold down the shift key, you can drag the center line (BFO) or the whole passband (PBS).

## Configuration tips

If you want to run OpenWebRX on a remote server instead of localhost, do not forget to set *server_hostname* in `config_webrx.py`, or you may get a WebSocket error.

DSP CPU usage can be fine-tuned in `plugins/dsp/csdr/plugin.py`: you can set transition bandwidths higher (thus degrade filter performance by decreasing the length of the kernel, but also decrease CPU usage), and also set `fft_size` lower.

If you constantly get *audio overrun* errors, you may change `audio_buffer_maximal_length_sec` in `openwebrx.js` from the default 1.7 to 3.

If you want a chat-box to the top of the page, <a href="https://gist.github.com/ha7ilm/15c4c5e4c80cef9b3144">here is a snippet</a> for you to include in `config_webrx.py`.

## Todo

Currently, clients use up a lot of bandwidth. This will be improved later.