ADS-B SDR and Dump1090 performance

August 29th, 2013 -- Posted in SDR | No Comments »

Quite some time ago I’ve been testing ADS-B Mode S reception with a RTL-SDR dongle and various embedded devices using SoC. The results were very good, and therefore I dediced to make an outdoor enclosure to be as closer to the antenna as possible. At first I was experimenting with the raspberry pi, but I soon figured that on busy places with lot of air traffic the raspberry processor was not enough. So I went with RK3066 solution and managed to capture even more airplanes passing by. The problem was that RK3066 stick was overheating and CPU speed was throttled by the kernel so hypothetically there were some signals I was missing. All this until I discovered a fork of antirez dump1090 on github by MalcomRobb. The GUI looked better, with more features, and then I read on github that the whole Mode S decoding part had been re-written with performance in mind.
When I installed this fork of dump1090 (that is in my opinion the best ADS-B software until now) I was excited to find out that my CPU load had dropped! Take a look below:

RK3066 load before and after

You can clearly see that dump1090 was lighter now, and the processor was working less. This has also a side effect on board temperature that decreased drastically after this software upgrade:
RK3066 CPU temperature

Also the next day I figured that indeed I had a problem with kernel clock throttling and that this new fork of dump1090 is much better in terms of performance because I was able to capture much more ADS-B messages!
Unique planes above

Now what remains is to integrate dump1090 to a web site and show it to you 🙂

GNUradio on Raspberry Pi

July 23rd, 2012 -- Posted in SDR | No Comments »

After about 2 days of messing with Debian on the Raspbery Pi I got an out of memory error during the compilation of UHD.
Seems like I have to cross compile. AGAIN…

[ 58%] Building CXX object lib/CMakeFiles/uhd.dir/usrp/usrp1/soft_time_ctrl.cpp.o
[ 59%] Building CXX object lib/CMakeFiles/uhd.dir/usrp/usrp1/usrp1_iface.cpp.o
[ 59%] Building CXX object lib/CMakeFiles/uhd.dir/usrp/usrp1/usrp1_impl.cpp.o

cc1plus: out of memory allocating 708240 bytes after a total of 22532096 bytes
make[2]: *** [lib/CMakeFiles/uhd.dir/usrp/usrp1/usrp1_impl.cpp.o] Error 1
make[1]: *** [lib/CMakeFiles/uhd.dir/all] Error 2
make: *** [all] Error 2

Software Defined Radio

August 26th, 2011 -- Posted in Uncategorized | No Comments »

When I was young, I had a dream. I imagined of one device that could replace them all. Why have a separate

-49mhz analog phone
-FM Radio
-TV tuner
-GSM cellphone
-DECT phone

Whilst all of them are based on RF?
Since I was a 15yo kid, of course I could only have this device in my dreams.
Now I see that time has come. With the advent of FPGA’s and modern electronics, you can have them ALL in ONE!

Why bother carrying all of this stuff, while funcube dongle exists?
Why buy expensive hardware that does very specific things, on very specific frequencies, and not write (or even re-use) some lines of code that run on generic hardware?

Why the fuck pay thousands of dollars for ICOM, YAESU and KENWOOD top-line machinery since what each of them has to show is their DSP unit? Create your own DSP unit! It’s just dragging n dropping a block!

Long live the Software Radio!
Thank you John Gilmore, Eric Blossom, Matt Ettus!