RTL2832U based software defined radios – OZ9AEC Website
RTL2832U-based DVB-T dongles are now supported by Gqrx SDR, see this announcement!
You may have noticed the recent buzz on the internet about using cheap DVB-T dongles as software defined radio receivers. It all started on this mailing list when V4L/DVB kernel developer Antti Palosaari discovered that the ezcap EzTV 668 DVB-T/FM/DAB USB dongle, which is based on the RTL2832U chip, can be used to stream raw I/Q samples to the host computer. It is in fact the way the device supports FM and DAB reception; raw I/Q is sent to the host where the application does the demodulation.
Once this was discovered it didn’t take long before Steve Markgraf of OsmoSDR created the rtl-sdr package that could be used to tune the dongle and dump I/Q data do a file for post processing. A few weeks late later Balint Seeber could announce the existence of an rtl_source_c GNU Radio block in his gr-baz package.
Obviously, I had to get one myself.
I followed the link on the OsmocomSDR page and ordered a few pieces from Dealextreme. I got an email on March 22 saying that order has been created and payment confirmed but nothing since then. Anyway, since I have a natural born suspicion against sites with such bombastic names, I decided not to rely on a single source and tried to order a dongle from another place. Thanks to @uhf_satcom I found out that CosyCave also sells the EzTV 666 and at £9.50 incl. VAT it is even cheaper than the $20, to which I will have to add about 150% duties and VAT. Okay, I admit that a web shop that sells herbs, medicine and a DVB-T dongle is not much less fishy than something called Dealextreme… but I can tell you now that they shipped very fast and since it came from the UK I have received it within 4 working days.
It is really amazing how much crap you get for £9.50: A DVB-T dongle, antenna, remote control and even a CD with software:
Finally, a few close-ups of the dongle:
As you can see the EzTV 666 comes with the Elonics E4000 tuner chip. As you can see there is not much info about this tuner besides some basic properties and a generic block diagram of a direct conversion I/Q demodulator.
The RTL2832U seems to be more common than one would think. About a year ago I bought a DVB-T dongle in a local supermarket here in Denmark. The brand is called AGK and it worked well on windows but I never got it to work under Linux so I threw it in a drawer where it has been until now. I decided to open it up and take a look at what is inside.
Surprise, surprise! An RTL2832U chip:
The tuner, however, is something called FC2580 from a Korean company called FCI:
As with the E4000, there is not much data available but is appears to support similar frequency range, i.e. cover both VHF and UHF up to 1.7 GHz. Once I get my EzTV 666 (and 668?) working, I will also try this one. It does look like I am not the only linux hacker interested in the RTL2832U+FC2580 combination, see for example this repository on Github.
In the meantime there is a compatibility list in progress over at Reddit.
Alexandru Csete
