After the blackout I was fiddling around with different alternatives to listen to the radio and get them back in working order using my RTL-SDR on the old laptop in case of repeated power outages and found this useful tool.
Thanks to the receiver"Radio Receiver" written entirely in JavaScript by Jacobo Tarrío, a software engineer from Santiago de Compostela living in New York, you can use an RTL-SDR from a web page, just like that. You don't need to install any of the usual software.
All you need to do is to have the necessary drivers installed, plug the dongle into your antenna and visit https://radio.ea1iti.es to start receiving signals. This, which in principle might seem of little use, makes it easier, lighter and faster to use the receiver on computers with few resources or even on an Android mobile phone.
Radio Receiver is an HTML5 website that uses an RTL-SDR to receive and digitise radio signals. It then demodulates these signals on the computer and plays the resulting audio through the computer's or mobile phone's speakers or headphones.
Most RTL-SDRs allow you to receive signals on any frequency between 30 and 1700 MHz. This includes interesting radio bands such as FM radio, maritime bands, airborne, weather stations, amateur radio, and in some countries, police, fire and other emergency services, etc.
You can also listen to frequencies below 30 MHz using an upconverter or the "direct sampling mode" of some models. These frequencies include, but are not limited to, AM radio, shortwave radio, HF amateur radio and number stations.
The radio receiver can also demodulate stereo FM, AM, narrowband FM, USB, LSB and CW. It has adjustable bandwidth filters so you can listen to Morse code transmissions or difficult and distant stations.
The source code for Radio Receiver is available on GitHub and this video explains how it works.
It is very simple to use. When you connect the RTL-SDR with the web https://radio.ea1iti.es open, just press Play to recognise it and link it. The configuration is very simple, although if you are not sure, it is also explained on the help page.
The settings are minimal, but allow you to tag frequencies and save them for a quick access list.
Radio Receiver must run in a browser that supports the HTML5 USB API. Typically this means a Chromium-based browser (Chrome, Edge, Opera) on a Windows, MacOS or Linux computer or any other Android device.
Radio Receiver was written to work with an RTL-2832U based receiver with an R820 or R828 (or compatible) tuner chip. RTL-SDR Blog V3 and V4 receivers are compatible, but older R820 or R860 based receivers should also work.
You may need to configure your computer to use an RTL-SDR if you are using Windows or Linux (MacOS, Android and Chrome OS usually work out of the box). For Windows, you must run the Zadig program to install a WinUSB driver and for Linux, you may need to configure your system to get raw USB access to the receiver.
I now have the laptop ready to work as a multiband radio by connecting the receiver to the cheap but cheerful Megaloop MLA-30+ antenna. Although internet access is necessary to use this option because you have to access a website, you can always leave any software installed in case you have another blackout.
