Amateur radio, space, technology and other geeky stuff by Alexandru Csete
For some time now I have been in great need of small and cheap AIS receivers that could be used for guiding various tracking equipment during Copenhagen Suborbitals missions. AIS stands for Automatic Identification System and is used by maritime vessels for reporting various status, including position, heading and speed.
Continue reading “A 2-channel AIS receiver using rtl-sdr and gnuais”
Take a Beaglebone, add an LCD cape and a £10 USB TV dongle, install librtlsdr and my rtlizer software and you have an awesome hand-held, real-time spectrum analyzer.
Continue reading “RTL-SDR spectrum analyzer on the Beaglebone”
Although I have had a Raspberry Pi rev B for several weeks now, it wasn’t until last night that I got a chance to try it out. Since several people have reported failed attempts at getting the Funcube Dongle Pro and Pro+ play nicely with the Raspberry Pi, I decided to take it as far as I could in those few hours. The result is this very brief tech note about how to make the Funcube Dongle Pro and Pro+ work on the Raspberry Pi.
Continue reading “The Funcube Dongle Pro and Pro+ on the Raspberry Pi”
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.
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.
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:
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.
Continue reading “FM transmissions over FO-29 linear transponder”
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.
Continue reading “FO-29 reception with Gqrx and Funcube Dongle (new recording)”
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.
Continue reading “APRS reception with Gqrx and Funcube Dongle”
Here is a short demo showing how to receive broadcast FM with Gqrx. This demo uses the Funcube Dongle, which is really not suited for broadcast FM reception. Gqrx does not employ any tricks to make it sound like it works properly – it just does straightforward FM demodulation with wide FM parameters and you will hear the lack of sufficient bandwidth as distortion on some stations (not all though).
Continue reading “Broadcast FM reception with Gqrx and Funcube Dongle”