Amateur radio, space technology and other geeky stuff by Alexandru Csete
Please note that the information in this article is out of date and needs updating. I will do my best to update it soon.
In a previous post I wrote about using the UT-100C DVB-T modulator on linux and I promised to follow up how to use the modulator with live video sources. In this post I am going to describe how to setup the modulator on a Raspiberry Pi equipped with a RaspiCam camera module, effectively turning the Pi into a live HDTV transmitter.
Building the UT-100 driver module on the Raspberry Pi can be done the same way as on the desktop. The only difference is that instead of “sudo apt-get install”-ing the kernel headers and sources we have to fetch them from the Raspberry Pi git repository and install them manually. Although my instructions are written with the UT-100C DVB-T modulator in mind, the procedure is applicable to other out of tree kernel modules as well.
In October last year I learned about the UT-100 series of DVB-T modulators available from a company in Taiwan. At that time I have already been working with software defined video broadcasting; however, I still found the idea of a small USB-stick modulator very appealing for use with embedded devices. In this post I have collected my notes about setting up and testing the UT-100 modulator on Linux.
Last week I have tested the RTL2832U-based ezcap EzTV666 DVB-T dongle on the air using various VHF signal.
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.