Posts tagged ‘rtl-sdr’

adsbox adsb receiver antenna rtlsdr gain

As adsbox did take too much CPU from my main server I moved adsbox to a banana pi zero w. Running Raspbian adsbox used about 200% of the 4 cores and 10% of the 512 MB headless system. That was OK for me and I wanted to extend the range of my rtlsdr antenne. I moved the antenna out side and was impressed about the exended range but nearby aircrafts did not show any more 🙁

As I want to see the nearby aircrafts, we are near düsseldorf in the landing lines and wanted the data of the aircrafts crossing the small home village 30km away from the DUS airport.

adsbox missed too much data or the rtlsdr dongle received too much signals. First I changed the adsbox call to use 4 threads for adsb decoding. That did not help.

Then I looked for the gain values to lower the reception signal strength. My rtlsdr RTL8232u supports gain values (found with rtl_test):

#Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6

I first started with 0.0 and got better nearby results but only a range of about 5km. Using 25.8 gives a range of 120km but too much airplanes (~39) and nearby losts. With the max gain I had more than 59 airplanes at a time. Finally I used 16.6, which still gives a range of 80km and ~5-10 airplanes.

Using the highest gain would give a very large range of ~250km but nearby signals get lost. And we ant to see mainly the nearby airplanes and now use a gain of 16.6.

The cpu usage is now down to 100% (quad core, so that is 25%) and the adsbox decocde threads are down to 15-25%.

rtl-sdr as flight radar receiver

Last week I got my rtl-sdr usb dongle by I ordered the “RTL-SDR Blog R820T2 RTL2832U 1PPM TCXO SMA Software Defined Radio with 2x Telescopic Antennas”.

Installation of the driver on the Debian Jessie system worked flawless I also first insalled and tested on a Raspberry Pi 2 B without hassles. But as I wanted to use the dongle alos as a radio scanner, I went over two the larger system.

After trying different Linux compatible software for Radio reception I went over to ADS reception. First I started with dump1090, which runs fine without any problems but I missed the similar display on a google map and airplane details. So I tried ADSbox. After getting the sqlite3 source and placing it nearby the adsbox directory, the compilation went fine and I now can watch some airplanes around my location.

ADSBox - Pale Moon_081

and, some time later (therefor different planes):

ADSBox - Pale Moon_083

Please know that the noise made by these airplanes is loud, even if they are 30000ft high and some kilometres away.

Now, I know which planes are there making the noise and where they are. Frustrating…I can not do anything against the noise but going indoor.