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So, now you have QtRadio running. Let's have some fun and do some useful things.

Full featured recording script

Since we have QtRadio, we have a lot of Radios over the world, which cover the frequency spectrum nearly from dc to uhf. So it is often the case you come along some interesting, odd, seldom transmissions, which you ever wanted to record and maybe analyse later.

The supplied script will, when started:

  • take you actual system time,
  • ask QtRadio for the actual tuned frequency,
  • will create a wav file stamped by the previos asked data (time+qrg.wav).
  • will, when you stopped recording, create a spectrum image from the recorded wav file.

So, first we need some little helpful programms. Check if you already have or install:

sudo apt-get install sox
sudo apt-get install hamlib-utils

Here is the recording script. Copy it into you favorite editor.

QRG="_$(exec rigctl -m2 -r f 2>&1)"
NAME=`date +%Y%m%d%H%M`
rec -r 8000 -c 1 $NAME$QRG.wav
echo "processing spectrogram..."
sox $NAME$QRG.wav -n spectrogram -x 1280 -y 720 -z 100 -t "$NAME$QRG.wav" -c '' -o $NAME$QRG.png
echo "...done !"
nano /usr/local/bin/qtradio_rec

make the script executable:

sudo chmod +x /usr/local/bin/qtradio_rec

Create you favorite recording location, for example:

mkdir QtRadio_Recordings

change to that directory:

cd QtRadio_Recordings

Fire up QtRadio before starting the recording-script and start the recording script from your recording directory:


you should now see this output from sox:

dl6kbg@ubuntu:~$ qtradio_rec 

Input File     : 'default' (alsa)
Channels       : 1
Sample Rate    : 8000
Precision      : 16-bit
Sample Encoding: 16-bit Signed Integer PCM

In:0.00% 00:00:21.50 [00:00:00.00] Out:164k  [      |      ]        Clip:0

while doing the first recording open pavucontrol and check if sox uses the right audio source. Select the following:


if you are done with your recording, press CRTL-C to quit the script and stop the recording. The script processes the spectrum image from the just recorded wave-file:

processing spectrogram...
...done !

when you now have a look into your recording directory, you should have something like this:

-rw-rw-r-- 1 dl6kbg dl6kbg  207665 2012-04-05 20:41 201204052041_3756000.png
-rw-rw-r-- 1 dl6kbg dl6kbg   32812 2012-04-05 20:41 201204052041_3756000.wav

You now have a time and frequency stamped audio file and the spectrum view from that audio file.

Sox spec.png

So, if you never want to miss to make a recording, open a terminal every time you use QtRadio and change in that terminal to your recording directory. Fire up "qtradio_rec" whenever you hear something interesting.

Enjoy and collect :-)

Squelch activated recordings

sudo nano /usr/local/bin/qtradio_rec_sql

and put in:

QRG="_$(exec rigctl -m2 -r f 2>&1)"
NAME=`date +%Y%m%d%H%M`
rec -r 8000 -c 1 $NAME$QRG.wav silence 1 0 -35d -1 00:00:05 -35d

make the script executable:

sudo chmod +x /usr/local/bin/qtradio_rec_sql

Frequency Scanning

stay tuned

Gnome Predict

stay tuned


John Williams (AC9HY) is running a hacked version of WSPR4.0 using hamlib net rigctl. He is trying to push the changes to K1JT at this time. Send an email to KE5SSH at gmail dot com to get more info.

Virtual Audio Cables

Found this nugget of info from a thread posted by Steve Haynal KF7O

Add the following 4 lines to /etc/pulse/default.pa and restart pulse:

load-module module-null-sink sink_name=vac1 sink_properties=device.description=Vac1
load-module module-null-sink sink_name=vac2 sink_properties=device.description=Vac2
load-module module-null-sink sink_name=vac3 sink_properties=device.description=Vac3
load-module module-null-sink sink_name=vac4 sink_properties=device.description=Vac4

sudo pulseaudio -k

These are similar to 4 Windows virtual audio cables. Set QtRadio to output to vac1 and then wsjtx to use vac1 as input.