Join 3,495 readers in helping fund MetaFilter (Hide)


Web Radio
June 5, 2010 11:54 PM   Subscribe

A WebSDR is a Software-Defined Radio receiver connected to the internet, allowing many listeners to listen and tune it simultaneously.
Websdr.org offers a list of such SDRs,
such as this one at the University of Twente Amateur Radio Club in Enschede, NL.
Tune in! The 80-meter AM band is currently hopping over there, the Germans are talking about oil spills and XYLs.
posted by dunkadunc (23 comments total) 30 users marked this as a favorite

 
I could listen to these all night. I love it! Makes me want to get my own SDR station, but I don't have anywhere to drop an antenna.
posted by Xoder at 12:17 AM on June 6, 2010 [1 favorite]


Darn... none of these have 4625 kHz.
posted by leviathan3k at 12:58 AM on June 6, 2010 [3 favorites]


cool
posted by caddis at 4:34 AM on June 6, 2010


I'm amazed at how amateur radio has managed to stay exciting in the Internet age. I'm listening to CW from a European beacon on a shared SDR in Eindhoven from New York. How many decades of technology are combined in this one activity?

On the downside, my code copying skills have atrophied, so I can't make out what any one is saying on the faster CQs.
posted by autopilot at 5:05 AM on June 6, 2010


Not real active in ham radio these days, but this is cool. Nice thing about metafilter; on fark the first 4 comments would have been snark about hams being old codgers. I'm sure it won't start here until comment 6-7. :-)
posted by randomkeystrike at 5:42 AM on June 6, 2010


It's the internet that got me interested in listening to the radio, actually. Before the internet, "radio" to me was either a rotation of the same 12 songs of whatever genre they catered to, conservative crackpots, and baseball broadcasts (I still can't decide if listening to baseball is more exciting than watching it). With the internet, my choices aren't limited to what's within a physical broadcast range, and the variety is increased a thousand fold. And I'm all for an improvement of older technologies. So thanks for this!
posted by Marisa Stole the Precious Thing at 6:44 AM on June 6, 2010


I will have to check this out later. I love listening to my SW radio (note: I'm under 30 years old) but my set can't receive SSB so I miss out on all but the rare amateurs that use AM.
posted by TrialByMedia at 8:07 AM on June 6, 2010


Wow, being able to see the noise across the spectrum is sweet. So much easier than spinning the dial until you hit something.
posted by iamgoat at 8:19 AM on June 6, 2010


Love it! Doesn't like my firefox, though safari seems to work ok. Also it doesn't have the upper 200 Khz of 80 and 40, so not much US phone.
My main antenna got knocked down last winter- haven't put it back up yet.

@Trial- I still like AM, when I can bust through all the SSB guys on 3885. I like boatanchor military stuff.
de W5GNF
posted by drhydro at 9:52 AM on June 6, 2010


iamgoat -- the waterfall display is incredibly useful. One of the most interesting parts is seeing a trunking system transmit -- you can see the frequency hopping pattern quite clearly as a sinusoidal pattern of bursts.
posted by autopilot at 10:57 AM on June 6, 2010


On that University of Twente feed, there's a weird-looking signal around 10112 kHz. Screenshot here. It's obviously artificial, but it just sounds like static and seems to be changing too slowly for data communications. Any ideas what it could be?
posted by teraflop at 11:06 AM on June 6, 2010


teraflop: Googling for that frequency turns up a few references to a low-bandwidth PSK-modulated (STANAG 4285) data signal on that frequency (or officially on 10111.5 kHz, apparently).
posted by hattifattener at 11:24 AM on June 6, 2010


How is it possible that each listener gets their own tuning ability? Is there actually a tuner for each listener or is there some wizardry that goes on with delivering a wideband signal somehow through the Internet and letting the user slice and dice it on the client side?
posted by crapmatic at 11:29 AM on June 6, 2010


Crapmatic: wizardry. Really, really awesome wizardry. A software-defined radio samples large blocks of frequency at the same time. Once that data is sitting in a computer you don't need separate tuners for each user - your "tuner" becomes a piece of software that just selects the right numbers out of the stream of data that's coming from the analogue-to-digital converter.

I doubt they're sending all the data for all seven bands to our browsers - more likely the slice'n'dice is happening server-side, and the client is receiving the waveform image (motion jpeg maybe?) and a single MP3 stream.

I hope they get rewind functionality soon - by the time I see something interesting on the waveform image, I've already missed it. PVR-style features would be a fairly obvious enhancement.
posted by Leon at 12:18 PM on June 6, 2010


Strange hearing HAM chatter from across half a world away. Stumbled across a sort of experimental music station of some sort on Twente's ~153khz -- even weirder given the eccentricities of shortwave...
posted by Ogre Lawless at 12:28 PM on June 6, 2010


How many decades of technology are combined in this one activity?

All of them.
posted by finite at 1:10 PM on June 6, 2010 [2 favorites]


My dad gave me his old shortwave radio back in the 90s when I was in elementary. I spent hours on that thing. I've been wanting to buy a high-end shortwave but I havent been able to justify it. This is SWEEET and will help quell that urge. Thanks!
posted by Brodiggitty at 1:51 PM on June 6, 2010


I really, really this would work. Java gives me nothing but a pure-blue unmoving waterfall display and no sound on whatever browser I try.
posted by Jimbob at 5:10 PM on June 6, 2010


SDR (and emergency communication here in earthquake country) is what is getting me back into amateur radio after a 10+ year absence.

It's kind of amazing we live in a time where this is possible with cheap consumer equipment.

I can't wait until I can purchase one of these systems a little more "off the rack"
posted by bottlebrushtree at 5:19 PM on June 6, 2010


I really want to like this, but I'm a little lost. Will somebody explain how to operate this, and where I can find cool things to listen to?
posted by Hoenikker at 11:08 AM on June 7, 2010


Well, when you find a moving "stream" of radio, just drag the little yellow tuner icon with your mouse to a spot that has a ribbon of whiteness, i.e. audio activity. Very thin, "jail bars" type patterns are just internal interference in the radio, while thicker patterns are real audio. When you drag, do it so that the whole icon moves, not just one side. Then if it doesn't sound right, tweak the positioning or play with the LSB/USB controls. There's not always activity on the bands, either... the best time to tune is late evening local time (wherever the receiver is) and the worst time is probably late morning when propagation is bad.
posted by crapmatic at 5:19 AM on June 8, 2010 [1 favorite]


Damn cool. I haven't really looked at HF in about 20 years, and this makes it a lot easier to just poke around.

de N2SXX
posted by dmd at 7:01 AM on June 8, 2010


forgot to mention,
de KC2DXE
posted by Xoder at 8:57 AM on June 8, 2010


« Older At a time when the US was turning its attention fr...  |  Fifty Contemporary Political I... Newer »


This thread has been archived and is closed to new comments