If you are using Ubuntu Linux you might have problems to open the Dutch WebSDR page. The problems appears in both, Firefox and Chrome. Canonical does not ship the Sun’s Java Runtime Environment anymore with Ubuntu. Instead they included OpenJDK and IcedTea, a Java Web browser plugin. Unfortunately, IcedTea does not work with the WebSDR Java Applet. However, there exists a solution. Read how I fixed the problem.
It’s quite easy to fix the problem. You need to replace OpenJDK and IcedTea with Sun’s Java JDK / JRE. In case this still does not work, find below some troubleshooting hints.
Install Sun’s Java JDK/JRE
With Ubuntu 10.04 the Sun Jave JDK/JRE has moved into the Ubuntu partner repository. In order to use it, you’ll need to register the repository within your Ubuntu.
Execute the following commands in a bash console:
sudo add-apt-repository “deb http://archive.canonical.com/ lucid partner”
Update the source list
sudo apt-get update
and finally install Sun’s JDK/JRE
sudo apt-get install sun-java6-jre sun-java6-plugin sun-java6-fonts
Accept the license agreement and start the installation process.
After the installation you might check if the Sun’s Java was installed correctly by the following command:
Open WebSDR in your Webbrower. If the waterfall diagrams are shown correctly and you can hear the audio, then everything works as expected. In case you don’t hear any audio, read the following troubleshooting hints:
Register manually Java sound service
Open sound.properties (on my system located in /etc/java-6-sun/ )
sudo gksudo gedit /etc/java-6-sun/sound.properties
add the following four lines in order to register the sound properly:
javax.sound.sampled.Clip=com.sun.media.sound.DirectAudioDeviceProvider javax.sound.sampled.Port=com.sun.media.sound.PortMixerProvider javax.sound.sampled.SourceDataLine=com.sun.media.sound.DirectAudioDeviceProvider javax.sound.sampled.TargetDataLine=com.sun.media.sound.DirectAudioDeviceProvider
Uninstall OpenJDK and IcedTea
With the installation of Sun’s JDK / JRE, OpenJDK and IcedTea should be removed automatically. In case you have problems, check if these packages have been removed correctly:
dpkg -l | grep openjdk dkpg -l | grep icedtea
In case nothing is displayed, OpenJDK and IcedTea have been removed correcty. If not, you might try the following commands:
apt-get purge openjdk-6-jdk apt-get purge icedtea6-plugin
Does this work for you? If so, please leave a short comment.