Sunday, December 16, 2012

Virtual Radar for a tenner - RTLSDR and ADSB: It works!

I had some time this morning to experiment with the RTLSDR USB dongle which I've previously mentioned. Designed as a DVB TV/DAB receiver, with different drivers, they can be used as a wide band scanning receiver. As I mentioned yesterday, I'd seen Pete 2E0SQL report success in decoding the ADSB transmissions from aircraft with his stick.

I used my latest USB dongle with the E820T tuner - having made sure that the drivers were up to date. The first ADSB decoder that I tried was the ADSBSharp program which you can download from here Having installed that - I started the program with the dongle plugged into a USB port and a small antenna which came with DVB stick plugged in. Immediately I could see that the dongle was decoding frames - and quite a few of them.

I wanted to try and plot them, so I started up ADSBScope which you can download here

From the menus, I selected Other/Network/Network setting and set the Raw Data CLIENT (not the server) to port 47806 which ADSBSharp was 'broadcasting' on. The URL should be set to 127.0.0.1

I then pressed the RAW Data Client icon - it's the right hand of the group of three 'network' icons on the icon bar. Lots of messages started appearing in the right hand pane, but very few position decodes. I filtered around with the filter but didn't see much improvement.

Honour was sort of satisfied as I knew the data was being decoded, but I wondered if if I could do better. I'd seen some discussion on Twitter about the RTL1090 software which would work with the RTLSDR dongle and should decode the data. I downloaded the program and installed it from the RTL1090 website

Running the program up, I could immediately it seeing aircraft and displaying 'Active Flight' data. However, even after reconfiguring ADSBScope's Raw Data Client to point at RTL1090 which was running on port 31001 ADSBScope was not displaying flight information.

I then remembered seeing in the ADSBSharp instructions that you had to configure the client to use AVR format. I had no idea what that was, but wondered if I should get RTL1090 to send the data to ADSBScope in AVR format. This was what cracked it! Simply start RTL1090 from a command prompt with the /AVR flag and the data will then be sent to ADSBScope and mapped.

I am surprised how sensitive the receiver is. Not as good as the LZ2RR  ADSB dongle, but as you can see from the map, the system is quite capable of receiving aircraft over distances of 20 to 50 miles away - even with a basic indoor antenna.



Definitely a great use for the DVB dongle, especially if you have been interested in Virtual Radar, but were put off by the prices!

7 comments:

Julian Moss said...

Very interesting, Tim. Time for a trip to eBay I think. :)

Graham Le Good said...

Thanks Tim, just tried my system out and it works well.
Those dongles are superb value at £10

G0MJW said...

Hi Tim,

I had a go with a USRP about a year ago - it worked reasonably well, but I didn't see the point of leaving it running, when you can do the same with planefinder. I have not tired ADSB with my TV dongle, I did manage to receive VHF/UHF but I found a better use for it, it is a good DAB receiver and can also be used to watch TV.

Beware of the ESD issues with cheap TV dongles and external aerials.

M6ODC said...

Hi Great Blog...

My NewSky TV28T Usb DVB/DAB/TV/FM RTL2832 Elonics E4000 tuner from CosyCave didnt work Julian so be careful. They do sell other tuner chips.

After a few days trying to get both 1090 and ADSB working and having no success (and thinking i was going mad) someone pointed me to rtl_test.exe (you plonk it in the folder where adsb.exe etc is and run from a command prompt rtl_test -t and it showed that my tuner range was 52-2171Mhz but my [E4K] L-band gap was 1087-1231 Mhz !so no ADSB decoding for me.. so be careful what 1 you order..

Ive ordered my new dongle from Jetvision.de (1090Mhz company) and its a ezCAP RTL2832 with RT802 tuner that definitely works on 1090Mhz.

As a newish Amateur radio op with no experince in much (but much enthusiasm) i can say that it was quite easy to get up and running and can happily decode POSCAG, Listening to Air etc all for a fraction of the price of the Funcube.

73 Glenn de M6ODC

Julian Moss said...

What I've ordered is a Creative Design New FM+DAB USB DVB-T RTL2832U+R820T. If it doesn't work then it was only six quid.

Julian, G4ILO

Gerard PE5GA said...

Thanks for the downloadlinks and the description, I got things running within 10 minutes.

Regard Gerard PE5GA

Tim said...

Great news, Gerard! Thanks for the feedback - have fun!

Tim

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