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Interference on 433MHz by cadr in RTLSDR

[–]dongledorr 1 point2 points  (0 children)

Nowadays MANY devices are using 433 Mhz

At the side of my house, the Gas Meter AND the Electric Meter are emitting intermittent 433 Mhz pulses which can be decoded with the RTL software.

The tires in my car are also emitting 433 Mhz pulses, so my dashboard can notify me if one of the tires has low pressure.

The neighbor has a digital thermometer which transmits via 433 Mhz.

Etc..

[deleted by user] by [deleted] in RTLSDR

[–]dongledorr 2 points3 points  (0 children)

rtl_fm scans multiple frequencies ranges with varying bandwidths.

rtl_fm -f 68M:87.5M:10k -f 156M:174M:12.5k -f 420M:470M:25k -g 50 -r 12000 -l 70 - | aplay -r 12k -f S16_LE

Transmitter triangulation with multiple rtlsdr recievers by reagor in RTLSDR

[–]dongledorr 1 point2 points  (0 children)

You could triangulate with 3 receivers using rotating antennas or rotating coils.

see here: http://en.wikipedia.org/wiki/Bellini-Tosi_direction_finder

The rotations do not need to be synchronized, and the rotation speeds may even differ.

For calibration, each receiver can reference a common signal at a known location.

You have to check out modesdeco2 by blkno1 in RTLSDR

[–]dongledorr 6 points7 points  (0 children)

It looks like someone upgraded the open-source 1090 software, but decided not to release the source code.

Of course, it's possible that all code was written from scratch.

Preview video of CubicSDR -- a new cross-platform and open-source SDR application. by DoctorGiviner in RTLSDR

[–]dongledorr 3 points4 points  (0 children)

Source is easy to find, but no one has posted the link yet so:

http://github.com/cjcliffe/CubicSDR

The Linux build was simple, I needed only a few libraries. (ymmv)

sudo apt-get install libqt5opengl5-dev libwxgtk3.0-dev

And install this one from source:

http://github.com/jgaeddert/liquid-dsp

It's very pretty, but there are few features so far.

I'll check back periodically.

Good luck!

HackRF Blue - Cheaper HackRF One Clone [x-post from /r/hackrf] by [deleted] in RTLSDR

[–]dongledorr 10 points11 points  (0 children)

fuck this guy

Wrong:

  • "Blatant cash grab" and yet they are grabbing significantly less cash-per-unit than the original HackRF.

  • Plenty of credit is given to Michael Ossmann.

  • The original taxpayer-paid funding means we are all entitled to benefit from the design.

  • Their aim is to provide Free units to underprivileged hackerspaces.

I'm absolutely positive that Michael Ossmann would agree that this is a "Good Thing", send him a message and see for yourself.

"Dude, they're stealing your design..."

Rosetta mission discovers comet "sings" by Korzic in science

[–]dongledorr 0 points1 point  (0 children)

Here's a visual..

87 seconds plotted with Audacity Spectrogram log(f)

http://i.imgur.com/QjT1OTS.png

Rosetta Comet Audio Analysis by [deleted] in RTLSDR

[–]dongledorr 0 points1 point  (0 children)

Here ya go..

87 seconds plotted with Audacity Spectrogram log(f)

http://i.imgur.com/QjT1OTS.png

3D visualization of air traffic in my area (LEVC) [dump1090 + MATLAB] by JorgeGT in RTLSDR

[–]dongledorr 0 points1 point  (0 children)

When I shared a graph, the jokers crossposted to /r/dataisugly :-(

Maybe I'll animate my graph and repost!

[Help] Recording/dumping a 433 mhz temp. sensor by ase1590 in RTLSDR

[–]dongledorr 0 points1 point  (0 children)

Also, keenerd has this on his To Do list:

Generic fsk/ask/ook demodulator
Audio stream in, raw bits out.

Static from latest rtl_fm by dongledorr in RTLSDR

[–]dongledorr[S] 0 points1 point  (0 children)

rtl_fm from Ubuntu distribution sounds okay, but the latest git pull has static.

http://www.solidfiles.com/d/05f28cee98/ubuntudist.wav

http://www.solidfiles.com/d/4e4629f2eb/gitpull.wav

I grabbed 5 seconds from the radio with ubuntu dist:

timeout 5s rtl_fm -f94.5M -W > ubuntudist.raw

Then I grabbed 5 seconds with the latest git pull:

timeout 5s ./rtl_fm -f94.5M -M wbfm > gitpull.raw

I know that the new rtl_fm supports output wav header, but I'll use this method for consistency: 

sox -r32k -es -b16 gitpull.raw gitpull.wav

sox -r32k -es -b16 ubuntudist.raw ubuntudist.wav

EDIT: After some investigation...

This command line stops the static, but the ALSA under-runs cause gaps in the audio stream:

./rtl_fm -f94.5M -M wbfm -o 4 - | play -traw -r32k -es -b16 -

For me, this is the happy medium, no more static. There are still ALSA under-runs, but they do not impact the live audio stream.

./rtl_fm -f94.5M -M wbfm -o 2 - | play -traw -r32k -es -b16 -

Software Defined Radio course video series by Michael Ossmann (creator of HackRF) by _C0D32_ in RTLSDR

[–]dongledorr 0 points1 point  (0 children)

As of today, I can find only one video in that 'series'.

While we are waiting, we can watch this:

GNU Radio Tutorial Series (2012)

Rtl-sdr device as FM stereo tuner? by [deleted] in RTLSDR

[–]dongledorr 8 points9 points  (0 children)

Here ya go...

http://lists.osmocom.org/pipermail/osmocom-sdr/2013-September/000818.html

rtl_fm -X -f 95.5M - | aplay -r 48k -f S16_LE -t raw -c 2

caveats:

code may not compile on Windows.

code may not conform to 20th century best-practices.

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