Tuesday, April 12, 2022

Web SDR: Free Access to the Diverse (and a bit crazy) World of Radio

Software Defined Radio, or SDR, is tremendously cool. For $30 bucks you can purchase a USB dongle which lets your phone or computer pick up a massive range of radio signals. You can use this for everything from listening to FM radio to collecting local utility meter data.

I recently discovered a variation on SDR: Web SDR. Web SDR is what it sounds like: folks take their SDR setups and make them available for use on the web. Using nothing but a web browser, you can tune into radio stations all over the world.

My hope was to show some practical use for this. Like say, getting first hand accounts of the invasion of Ukraine by listening to Polish or Russian SDRs. Or, closer to home, I was thinking I could use a Washington DC based SDR to listen to CB radio chatter among protesters involved in the 'People's Convoy' that circled DC's Beltway.

Not surprisingly, I didn't (and still don't) have the knowledge or patience to extract any brilliant audio from any of the SDRs hosted at websdr.org.

When I slowed down and focused on just local SDRs (one here, the other here) I did start to get a picture of what kind of chatter is available over the air.

Even just casual listening let me appreciate that I could pick up everything from far off radio stations to local Ham Radio operators kibbitzing with each other. I found channels publishing Morse code,  the weather or just announcing the time. I heard truckers chatting on the Beltway, preppers discussing immanent food collapse, and preachers talking about the Israelite's.

I'd say that the radio spectrum appears to mimic the Internet in its diversity of topics, characters and content, but that's almost certainly backwards. The hodgepodge of content that is available on the radio almost certainly existed far before there was an Internet. Before URLs there were radio frequencies and before email addresses there were call signs.

To ground these musings into something concrete, I give you the following 173 second of video. Using the local DC Web SDRs linked above, I captured a slew of audio clips. I edited them down and mashed them together to form this video. Think of it as a tiny sampler what you can find on a Web SDR.

I still have hopes of using local or distant SDRs for something practical. For now, however, I'm satisfied with just having a unique appreciation for what's being streamed into the ether.

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