15 Bucks SDR with DVB-T USB stick (2MSample IQ ) :)

[Darin.K]

I was distracted by running the SDR on my BeagleBone, I should finish up my VIs and post the direct USB interface.  In the meantime I have picked up an R820T-based tuner for dirt-cheap on EBay, and while the tuning range is less than the Elonics tuner the noise floor is lower.  It is a winner as a replacement for the E4000.

I think if I cover those two tuners then the USB interface should be useful to most people.  Wrapping the rtl-sdr functions works well, but I like to dig around at a lower level, and using libusb functionality directly is quite interesting.  The tcp interface is useful for testing, but not quite as performant.

By far the biggest pain was getting a useful interface for streaming audio from LV. 

Another fun hack was to catch the signals from my wireless weather station sensors, still reverse engineering a couple of them. 

[Henrik_Volkers]

One nice event for HAM radio freaks and SDR(#) users in about 5:15 hours:

http://missionjuno.swri.edu/hijuno/

What is this?

NASA's Juno spacecraft will fly past Earth on October 9, 2013 to receive a gravity assist from our planet, putting it on course for Jupiter. To celebrate this event, the Juno mission is inviting amateur radio operators around the world to say "HI" to Juno in a coordinated Morse Code message. Juno's radio & plasma wave experiment, called Waves, should be able to detect the message if enough people participate. So please join in, and help spread the word to fellow amateur radio enthusiasts!

If I would be allowed to send (Good generator and amplifiers are flying around 🙂 , I would do the keying with a RS232 DTR line controlled by labview 😄 )

[LV_Pro]

Tnx Henrik!  De WA2UPA   Sadly, no way to get on from here but I'll send a message to a friend who has equipment ready to go!

P

[Darin.K]

I am not sure the phrase "mission creep" adaquately describes what is going on here.  Just an update on what I have been playing around with.

Got the FM demod working.  Locked to stereo pilot and got stereo demod working.  Locked to RDS signal and got the station info (if a syndrome is something you think you should see a doctor about, this step is a bit involved).

Now it gets fun.  I wanted a FM DAR (digital audio recorder), you know, pause live radio and the like.  Figured a good step would be to use mp3 compression to encode the audio.  This requires an mp3 decoder to test the encoding. 

Lesson:  Getting the FM demod to work was a fair amount of work, much of it "blind".  Very hard to test individual pieces, you need to have all of the steps going (configure SDR, transfer data, convert to IQ, mix down so signal is at baseband, filter,  lock to stereo pilot, combine channel data,...).  Working is half of the battle, it must work in real time.  The lesson is to prepare for success, the first sounds were a bit like banshee screaming, so I always kind of expected that.  But, when you hit run and it works, it is one of the great moments that stick with you.  Try not to spoil it by having your SDR tuned to an adult contempo station.  Now I have some lame Chumbawumba song burned into my brain....

I tried to apply that to my mp3 decoder.  My chosen Metallica tune was set, and it was a bit out of whack.  Unfortunately I then tried it on a Pete the Cat mp3 file, which worked great.  Another moment spoiled, although my son came running in.  A few tweaks later and I was head banging (one missing reverse array was enough to go from hi-fidelity to fingernails on chalkboard).  This led to a fun stretch, I was not rocking out to my metal collection, I was "unit testing". 

Next journey:  parse tags for things like artist and album art.

Next journey:  lookup unknown tracks in online database.

Next journey:  why not listen to internet radio?  almost worked out of the box, implemented my own http get and post for fun.  Had glitches until I figured out how the track names were being embedded in the stream.

Next journey:  why not accept gzip compression in my http get and decode in LV?

Next journey:  why not get album art for the songs playing on the internet?

Next journey:  why not decode the album art jpegs in LV?  (Not too hard, all of the -PEGs use similar bags of tricks)

Next journey:  what about my CDs?

Next journey:  what about getting the CD-text from my CDs?

Next journey:  what about looking up the CD info online?

Next journey:  what about fingerprinting songs for CDs not found?  (right now I use a third-party API, I hope to reinvent the wheel in LV)

Next journey:  what about fingerprinting songs from live FM?  (get some crazy results, but it helps to fine tune when possible with RDS data)

Next journey:  what about podcasts?

Now I just need to polish my icon:

Eventually I will get back to finish my mp3 encoder and get the DAR working, eventually.  Then it is on to AAC, and perhaps, gulp, some video decompression.  How did I get here from plugging in a simple little USB device?

Final lesson for now:  even crappy music sounds good when you have written the code which takes it from a string of bits to music.

[tst]

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@Darin.K wrote:
...lame Chumbawumba song

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Does not compute.

You're never gonna keep me down.

[Henrik_Volkers]

Darin that's sounds COOL 😄

Do you know this one:

My journey into FM-RDS [30c3]

[Darin.K]

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@Henrik_Volkers wrote:

Darin that's sounds COOL 😄

Do you know this one:

My journey into FM-RDS [30c3]

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That was a pretty interesting talk, but I would have like to have bought the speaker a double espresso beforehand so it could have been done in 20 minutes instead of 36.

[altenbach]

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@Darin.K wrote:That was a pretty interesting talk, but I would have like to have bought the speaker a double espresso beforehand so it could have been done in 20 minutes instead of 36.

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Were you thinking about the psychoactive or diuretic effects of caffeine? Both would have probably pushed things in the right direction. 🙂

[alipio]

Hi all.

Any news about RTLSDR low level control from Labview?.

Best regards.

Alipio.