I was testing the Gqrx FM stereo code by Alex Grinkov using an RTL-SDR dongle when I noticed that the recently added auto-gain in the driver can be quite useful.
receiver
NOAA APT reception with Gqrx and rtlsdr
About a year ago I posted a step-by-step guide about how to receive NOAA APT weather satellite images using Gqrx SDR and the Funcube Dongle. Today, I tried to repeat the procedure using my ezcap eztv666 rtlsdr dongle with very good results.
Gqrx with RTL-SDR and UHD support
Support for RTL2832U-based DVB-T dongles and USRP devices from Ettus Research is now available in the Gqrx source code repository.
Support for RTL2832U-based DVB-T devices is available via the rtl-sdr and gr-osmosdr libraries. This also provides support for Ettus Research USRP’s if the gr-uhd package has been installed prior to compiling gr-osmosdr. A complete build from scratch that would support all hardware devices would thus include the following steps:
FM transmissions over FO-29 linear transponder
I have previously written about interference from FM stations on the HO-68 linear transponder. Now it appears the other satellites with linear transponders also suffer from local FM traffic by people who haven’t got a clue that they are transmitting in the satellite uplink segment of the 2 meter band.
FO-29 reception with Gqrx and Funcube Dongle (new recording)
Here is a new recording showing an updated Gqrx receiving the FO-29 amateur radio satellite using the Funcube Dongle. Previous recordings used an early version of Gqrx. It was a very quiet pass, most notable thing was probably the Russian and Spanish hams using FM. They probably don’t have a clue that their signal comes over a satellite transponder. Another video recording focusing on the FM transmissions during this FO-29 pass is available here.
APRS reception with Gqrx and Funcube Dongle
I don’t think I ever posted a video showing the built-in AFSK1200 demodulator and decoder in Gqrx, so here it is. The video show local APRS traffic in Copenhagen on a Sunday afternoon. I also tried to receive from the ISS but nothing heard this time.
Fun with the Funcube Dongle
I was playing with my Funcube Dongle last Saturday testing Gqrx for the long awaited 2.0 release. I was using the Funcube Dongle together with the shortwave converter I got some time ago and a 5 meter long wire attached via an antenna tuner. Amongst all the traffic there is on shortwaves I recorded these two transmissions: UVB-76 aka. The Buzzer, and whistle like signal believed to be a radar in Israel.
EzTV666 DVB-T dongle on the air
Last week I have tested the RTL2832U-based ezcap EzTV666 DVB-T dongle on the air using various VHF signal.
RTL2832U based software defined radios
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.
Gqrx and Pulseaudio
Just a quick note that Gqrx now uses pulseaudio for all audio I/O, which includes I/Q input from the Funcube Dongle.