Online Ham Radio Receiver
Phil Pilgrim (PhiPi)
Posts: 23,514
This is one of the most amazing web apps I've ever seen: websdr.ewi.utwente.nl:8901/.
It's a software-defined shortwave receiver that you can tune from your computer. I'm really blown away!
-Phil
It's a software-defined shortwave receiver that you can tune from your computer. I'm really blown away!
-Phil
Comments
groups.yahoo.com/group/SoftRock40/
I built one a few years ago.
I'm thinking of using an XMOS chip to do the DSP, instead of a PC. Ultimately, I'd like to do the whole thing with three chips - an ADC, a small FPGA, and an XMOS chip.
Leon
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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 10/25/2009 7:05:41 PM GMT
Fun listening to things I can't pick up from my location in the south USA.
Leon,
Would it be an unusual experiment to have several of these stationed around the world, sweep through the frequences, log the signal strengths, and compare the results - as an indirect indicator of various atmospheric phenomena?
- H
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Leon
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Amateur radio callsign: G1HSM
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You can identify the type of transmission from the waterfall display - mostly CW and SSB in that part of the band.
I ought to dig out my old Softrock board and get it working again.
Leon
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Amateur radio callsign: G1HSM
Post Edited (Leon) : 10/25/2009 9:11:40 PM GMT
Is it possible, with software alone, to determine whether an SSB signal is USB or LSB? If I recall the basic theory right, SSB doesn't have a carrier (which could be a reference).
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Leon
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Amateur radio callsign: G1HSM
You realize this means you have a serious problem, but we like you!
No, that's really way cool!!
I was playing with it the other night though and don't know if this was a "java burp" or not but something, did a sweep across the entire band lowest to highest in all three bands ... took about a second, but it was a visual "bell curve" ... any idea what that could have been?
At first I thought it might be a local radar, but it's too infrequent ... I just saw it again a few minutes ago
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Post Edited (Beau Schwabe (Parallax)) : 10/26/2009 6:12:35 AM GMT
I can't get it out of my mind that the Prop could replace — or at least augment — a lot of the circuitry on that SoftRock40 board. I need to revisit the Propeller radio stuff and see if it can be pushed further.
BTW, I haven't seen the sweeping signal effect you noticed, although on my iMac the graphics from that site tend to flash and blink a lot.
-Phil
Leon
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Amateur radio callsign: G1HSM
erco KM6DS
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·"If you build it, they will come."
Paul
KC9KST
There, that should generate some opinionated replies, perhaps as spirited as Phil's rebuttal to my old post espousing the inherent limitations of differential steering.
All this makes me want to dust off my umpteen Heathkits·(and Philco 1960 Predicta TV·& 1941 floor radio/phono)·and heat the house with those·sweet glowing filaments! Hooked on Microphonics...
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·"If you build it, they will come."
We've kinda gone the same route, license-wise. I started out WN9HJK -> WA9HJK as a teen, did some RTTY with a donated WU teleprinter, but let it all lapse in college and sold my gear. ('Too much other fun stuff to do!
I don't disagree entirely about the code requirement. But I'm more concerned about the dirth of young people getting into the hobby. Last spring, I went to an open house hosted by the local ham club. What a klatsch of old farts! Knowledgable old farts, to be sure, but ancient. I was easily the youngest person there! I brought up this issue with a club member that I know, and he admitted that they were doing little if anything to attract a younger crowd.
It doesn't seem as if the ARRL is helping much in this regard, either, judging by their publications. I subscribed to QEX, which is supposed to be for bleeding-edge experimentalists. The first issue that arrived had a photo of a vacuum tube Philbrick op-amp on the cover! And the accompanying article was mostly a nostalgic retrospective. Moreover, the black-and-white print on glossy paper and page layout reminded me of the QSTs my uncle gave me back in the '60s. I wouldn't be terribly surprised to learn that they're printed with lead type and zinc photoengravings using a letterpress!
There's so much cool techie stuff that can be accomplished with software-defined radio, though. It's a logical extension to all the microcontroller work that we do. Getting a Tech license is an entr
Although I don't have my license yet, I've been looking at ham stuff off and on for decades - primarily because of what you can learn from it. Had always known that CW would be needed. So I was disappointed actually to learn that the code requirement was dropped. I'm lazy - no pain, no learny. Sure, there's software to decode code. But isn't that like non-alcoholic beer? Plenty of calories, but no kick.
> But I'm more concerned about the dirth of young people getting into the hobby. ...
> ... the local ham club. What a klatsch of old farts! ...
> ... they were doing little if anything to attract a younger crowd
Neither the dropping of the code requirement, nor avoidance of odorous ham clubs is what's keeping young people from getting interested. It's much more simple. Consider, back in the day, when we could fire up a Heathkit and bask in the warm filament glow, Ham radio was *the coolest electronics thing going*. Or maybe home-brew sound gear. (Bet the ratio of hams who've built their own speaker cab's is near 1-to-1 [noparse]:)[/noparse]
What have we got today that's electronic geeky freaky?
Right!
Zillions of things: internet, programming, micros, iPods, uPods, Wee-All-Pods ... ham simply has too much competition.
This does have some interesting consequences though. As the 'old farts' pass away (a stinky metaphor :-P) those left will have to become more knowledgable in the craft. The internet as a resource will keep it all improving, IMO, despite falling numbers. The site Phil found is an excellent example of the 'wow factor' that can attract new folks.
- H
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Got my license when I went to college (electronics) and bought a few items, but never used it afterwards.
I have my Basic and Advanced (think extra class? without morse endorsement)
I recently joined the local club to find Morse requirements gone. Great....I always had trouble hearing the beeps properly....but I also think...geez, it was a mark of pride to get the 5wpm and 15wpm (whatever they were).
We actually just had our HamFest on Saturday. It wasn't the biggest turnout...but not the lowest either!
Lots of neat things....a lot of which I don't remember.
Our local club is very active with volunteering for festivals and parades.
There's also an active ARES (Amateur Radio Emergency Service) too....of course, with a dozen tornado's roaring through the area (first time in recorded history for that many)...well, enrollment is up!
I'm rather young for the club...34...but enjoy the stories!
I'm written a few articles for their newsletter with microprocessors in mind, and the responses have been positive and with lots of questions...or no questions at all (stumped them?).
It does seem that the experimenting Hams are a bit cautious about getting in to software types of systems. They don't get to mod/patch the computers to get extra abilities....it's all software.
Ah well, it'll die eventually, but not before a few more guys get in trouble for putting ugly antennas up! [noparse];)[/noparse]
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<FONT>Steve
What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!
Still, this online radio is interesting.
some of this stuff is bleeding edge.
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Because after the Atomic Flame Deluge comes (in the near future) and after the Great Simplification, ignorant hordes of maimed and deformed survivors will condemn all knowledge, all technology, all science that allowed that terrible thing to happen. Scientists, teachers, all learned people (including Parallax forum members) will be persecuted and killed or driven into hiding. The Internet will be destroyed, and books will be burned. The only way for technical knowledge to survive is secretly hidden in the minds of men forced to remain silent for many dozens of years, covertly transcribing their knowledge to hidden writings and being secretly preserved and passed down from generation to generation...
If you haven't read "A Canticle for Liebowitz", you should! Don't hope for a movie version, it could never be done justice.
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·"If you build it, they will come."
The equipment doesn't have to be ancient. There's enough snazzy new stuff out there to make the most jaded MMPG user drool. (If something like this doesn't stimulate your techno-lust, please turn in your geek badge immediately!) Or, if you're so inclined, you can build your own. Lots of people do; and, as long as you put out a clean signal, you don't need an FCC equipment certification to use it, like you might for home-built Part 15 emitters.
One of the advantages conferred by ham radio is disintermediation. Sure, we live in a connected world, but that connectedness relies on a web of intermediaries. With a ham license, you gain total independence from all that. Moreover, for long-distance wireless data transmission, a ham license provides a simple means to experiment to your heart's content.
I get the bit about "sitting at a table and listening to somebody on the other side of the world who is probably three or four times my age", though. That part of the hobby never appealed to me, either. In fact, it's downright boring, as far as I'm concerned. But data transmission, fiddling with different modulation/demodulation and encoding techniques, learning about analog and RF circuitry — all those things are intriguing and can be done without encountering a single old person!
Getting a Tech class license is a piece of cake, and you can probably find a convenient exam session right on campus. Now, do you have any excuse not to?
-Phil
Post Edited (Phil Pilgrim (PhiPi)) : 10/26/2009 9:22:25 PM GMT
Ken N8SYG
Back in the '60's I had an old Heathkit 4 band radio I'd sit up listening to for hours sometimes. This brings back some old memories!
This would be an ideal alternative to going out and buying another radio!
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Prune Free.
Hamfolks, what keywords should we search for ?
Google usually finds everything (... except·missing socks).
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I grew up in a ham family, though, so a lot of the stuff wasn't unfamiliar to me (apparently I knew enough to pass the General test). But like SRLM, I had no interest in sitting in the basement talking with people by radio. I still really don't - I have exactly one HF contact, with my brother in Tennessee, checking to make sure that I'd set up the equipment he loaned me correctly. I'd be interested in learning about emergency services, but I just don't have time for that right now. I'll be elderly in about a decade anyway, so I can become a real ham at that point.
The intended use is to pipe in audio from your RCVR to the sound card microphone. Lacking a RCVR, it is still·useful & fun·to download the W1AW code practice session .wav files and have the program display them on-screen.
BTW, CW=continuous wave,·ham·lingo for using code instead of voice transmission. CW lovers are purists, a shrinking niche group within the shrinking ham world. CW signals will usually go farther than voice signals. Another niche group are the low-power QRP users, who try to "work the world" on very low TX power, like 10 watts or less. It becomes an efficiency addiction, trying to make the most of antenna directivity & efficiency (low SWR), and atmospheric conditions, including sunspot activity. There is a certain elegance to this approach,·diametrically·opposed to the power users who use 2 kilowatt amplifiers to simply "punch through" the interference (QRM).
There's no shortage of people asking "why learn morse code", and the answer is different for everyone. Understanding CW is an art form, it's a skill, it's like a foreign language. Seeing old-timers converse at 40+ WPM is amazing.·Most don't even write down the letters, they listen for words and just keep the conversation in their head.
Sending clean code is different from copying code. There are straight keys, Vibro-plex "bugs", and electronic keyers. Old brass telegraph straight keys are very cool, elegant, and collectible. My homebuilt 30-year-old WB4VVF Accukeyer still works perfectly, and it's fun just to break it out now & then to beep out practice code.
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·"If you build it, they will come."
Ultimate cool would be 2 geosynchronous satellites with nice sized
dish antennas and a log periodic, parked to give coverage of the entire earth,
one on each side above the equator.
They could pick up everything from shortwave to microwave and send the
entire spectrum down to ground stations and put it on the web.
At times the lower shortwave frequencies would not reach the sats due
to the charged layers of the atmosphere though.
You could tune in to about anything.... some frequencies would be very noisy
though...just imagine the racket on the FRS channels!
I just bet that the government already has a setup like this in operation.
This setup would mean that any rf signal you emitted on the ground would be
available worldwide on the web.
14mhz to 2.5ghz would be the perfect range to send back to the ground stations.
The range could be translated to a range above 20ghz and sent down at very low
power.
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"Where am I? Where am I going? Why am I in a handbasket?"
Post Edited (HollyMinkowski) : 10/26/2009 11:51:53 PM GMT
Click on J-Track 3D, and then click to run the aplet. Real-time satellite data loads and you will see a globe and all the various satellites in their relative positions. Use the shortcut menu listed there to zoom in & out, and click & drag the 3D image to rotate it around. The geostationary/geosynchronous sats are way out in equatorial orbits. Other sats are only a few hundred miles up.·There's quite a lot of sats out there. You can click on any dot to see what the sat's name is. And yes, you can see the ISS and shuttle when it's up there. Zoom in, you can see the sat moving in real time.
Hams have their own satellites up there, too. See http://en.wikipedia.org/wiki/OSCAR
If you like tracking the ISS, check out http://spaceflight.nasa.gov/realdata/sightings/cities/skywatch.cgi?country=United+States·which tells you when you can see it fly over your city. It has to be dawn or dusk, and it appears as a fast-moving star, easily seen with the naked eye.
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·"If you build it, they will come."
I do agree about the data transmission part though. That was what interested me in the Amateur radio world, but I don't really have any reason to enter. I can just buy a pair of transceivers on the ISM bands, and use those straight out the box.*
"Shame," you say. "Today's youth aren't curious are inventive like we were. Remember the good old days of [noparse][[/noparse]fill in personal memories here]?"
Nope, that's not it. I just don't see why I should put effort and limited money into something that somebody can do much better and much cheaper. I'd rather spend my time building something that can't be mass produced in China, or at least something that hasn't been yet.
*Okay, so maybe the boxed solutions are limited in range (16 miles for the X-Tend modules). But, I don't have a car (I have my bike), and I don't have anywhere to put a transmitter further than maybe a mile. Why would I need more?
Post Edited (SRLM) : 10/27/2009 1:11:25 AM GMT
There are build-from-scratch plans aplenty that not only result in quality, usable, modern equipment, but can save money over store-bought items. And if that doesn't float your boat, there's always eBay. That's how I got my two transceivers. 'Paid about $130 apiece for them. They're not tomorrow's models, but they're not last decade's either. Housed in enclosures smaller than a pack of cigarettes*, they transmit on two VHF bands and receive on all frequencies (excluding cell phones) from 500KHz to 1000MHz (AM, FM, and NBFM; no BFO, though, for CW or SSB, but making one should be easy).
But you're busy with school and, I presume, an active social life. And that's okay. I was, too, when I was in college, and I let my license lapse. But I guess my point is that there's more to it than just the end result. You can learn a lot by doing and can enjoy the process, sometimes even more than actually using the product of your efforts.
-Phil
* "pack of cigarettes": Gad! We really need another benchmark for "small". Can anybody think of one, about the same size, that most people can relate to?
Sure, the journey is important, but my feet (or hands or head) can only take me so far. That's what pictures (products) are for: I expect that sometime before I die I will hobo across at least one continent, but seven? I have to make a critical decision on which to choose, and just read about the others. The same applies to hobbies. I suppose I could design a custom microcontroller using discrete logic chips, interface it to a home built radio transceiver, and send the data in an ulta low frequency band. But ultimately, I think I could be more productive (and repay my debt to society) if I make educated decisions about what challenges to tackle and what to leave to others.
Ultimately, I guess it may boil down to personal preference. I don't really like RF that much, and EE isn't much better. I'd much rather program or do something mechanical. Maybe I am choosing the road around the mountain instead of over it?
Ipod Classic? Smart Phone? Graphing Calculator?