The big shack renovation meant I had to put all my stuff back into boxes. No problem spending some time without my rigs and tools, but I didn’t want to spend a couple of months without any form of radio. So I left out the RTL-SDR dongle and a mobile whip to see if I could get some more out of it than digital TV. I have had the dongle for a while now, but I was never impressed by it. Lots of white noise and very few signals to be seen on the waterfall. I even boxed it up nicely to avoid EMI.
The first step was to see if the dongle still worked by scanning the DVB-T bands. After installing the necessary RTL-SDR packages I fired up VLC to see if it would decode signals. There are packages like MythTV and MeTV that can let you watch DVB-T, but I don’t like cluttering up my system especially since VLC is such a versatile piece of software. For it to work you need to open an console though, but the internet is awash with good tutorials to help you get it done.
Step 1: install dvb-apps with
sudo apt-get install dvb-apps
Step 2: use the scan application that comes with dvb-apps:
scan /usr/share/dvb/dvb-t/tw-All > channels.conf
Step 3: open the channels.conf file with VLC
Step 4: choose your favourite channel and enjoy
Most of the time Linux provides an alternative and in this case it’s w_scan:
w_scan -X -c TW
substitute your own country code in place of TW; a list can be retrieved by issuing the command
w_scan -c ?
Before I knew it I was watching the WBSC Premier 12 baseball games and found out Taiwan’s public broadcaster is airing Person of Interest. Usually I find that watching tele is just a big waste of time, but I do also find that it is the only time I am not physically active and I do need to rest more. My wife likes PoI too, so now we have a date every Monday through Wednesday at 10.
The FM band was another check to see if the RTL-SDR dongle works as advertised. On Windows the prevalent SDR software is SDR#. On Linux this is GQRX, which is based on GNU Radio, a very powerful but complex piece of software. Before you can start GQRX you need to deactivate the dvb_usb_rtl28xxu driver as this conflicts with the rtl2832 driver. Issue the following command:
sudo rmmod dvb_usb_rtl28xxu. If you never watch TV then blacklist the driver in order for it to be never loaded when you insert the dongle.
I could indeed receive FM broadcasts, but as many as I could with my Sangean ATS-909, so no big win there. GQRX also has a build in AFSK demodulator and I tried to decode some APRS signals on our local frequency of 144.640 MHz. I could hear signals and see them on the waterfall, but not decode them. After trying some other antennas and even taking everything outside in the open I grew a bit frustrated and searched for some other signals to decode. Tracking aircraft using ASD-B seemed fun (G4VXE wrote about it before here on AmateurRadio.com ) so I tried to set that up. And in doing so I got a big surprise.
[to be continued]