WebSDR & Java fix for Ubuntu Linux

WebSDR & Linux how it worksIf 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:

java -version

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:


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.

About Tobias (DH1TW)

Self-confessed Starbucks addict. Loves to travel around the globe. Enjoys the technical preparations of Amateur-Radio contests as much as the contests themselves. Engineer by nature. Entrepreneur. For more, follow him @DH1TW


  1. Note: as publish on your blog, the first command does not work, – the wrong type of quotes are used, or at least that was the results when I used the “cut and paste” on my command line and keyboard.

    But it works if the quotes are changed!

    And, Thanks – I need that!

    Eldon – WA0UWH – http://WA0UWH.blogspot.com

  2. TNX for nice site.
    GL on DX’ing & contest

  3. Jonathan Marsden - AF6YF says:

    WA0UWH is correct, the quotes in the article are MS Word “smart quotes” which is odd for an article about Ubuntu!

    Also, I’m running Ubuntu 10.04 64bit here and the site linked to in the article works for me as is, using openjdk and icedtea (in Firefox). So while this looks like a nice tutorial on installing the Sun JDK, it doesn’t seem to be necessary to do that in order to use WebSDR 🙂

    • Openjdk worked for a few hours. Then only a tone and off. Now with Sun JRE everything works except Austria…
      Rupert (HS8/DL3NO)

  4. PE1R says:

    @ AF6YF Openjdk compiled in 32 bit never worked for me
    also a typo in dkpg -l | grep icedtea

    You can manually add the package source in Synaptic

    deb http://archive.canonical.com/ lucid partner

    Push the blue reload button in Synaptic

    Remove the Open-jdk and Ice tea packages

    Install sun-java6-jre , sun-java6-plugin , sun-java6-fonts packages

    Current version archive version is ; sun-java6-jre 6.20dlj-1ubuntu3

    Current Oracle version is 6 version 21

    73 , Ruud

  5. Jochen-7J1AJV says:

    Dear OMs

    Obviously icedtea is somehow incompatible with the WebSDR Java Applet. It seems that the same Java Applet is used in other sites as well. Same problem.
    For administrative reasons I would like to follow to LTS path, I am administrating our 3 “family” PCs. So hope to get a fix with icedtea. (I somehow believe the problem is on their side).

    73, de Jochen 7J1AJV

  6. iw0hdv says:

    I installed the following packets from Applications->Ubuntu Software Center, selecting

    Getting software -> Canonical partners

    write Java in search field

    next install:
    Sun Java 6.0 Plugin
    Sun Java(TM) Runtime Environment (JRE) 6 (architecture dependent files)
    Sun Java(TM) Runtime Environment (JRE) 6 (architecture independent files)
    Lucida TrueType fonts (from the Sun JRE)

    restart Firefox and all works.

  7. oe1gca says:

    I followed the instructions to fix the no-sound problem – but it still does not work.
    dmesg says:

    [ 2855.384600] type=1503 audit(1284638383.265:125): operation=”open” pid=4891 parent=4810 profile=”/usr/lib/firefox-3.6.9/firefox-*bin//firefox_java” requested_mask=”::r” denied_mask=”::r” fsuid=1000 ouid=0 name=”/dev/snd/controlC0″

    Any ideas?

  8. Grant says:

    Does anyone have a way to use jack with the websdr and fldigi or gpsk? it’d be really cool to be able to use multiple browser tabs sending audio to fldigi for decoding.


  9. mni tnx, Tobias, works great and out of the box
    guenter DL7LA

    • guenter says:

      Hi, Tobias,
      I guess the Firefox peaople messed it up again with their last update a few days ago: now failure all along the line again. Sun-Java is installed like

      java version “1.6.0_26”
      Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
      Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)

      but to no avail. FF claims that there is no java existent nor active. All the openjdk stuff and iced tea I had purged.

      Anyone out there with ideas about a browser that works?


    • Hi Guenter,
      I switched a while ago to MacOs. Basically Linux on steroids 🙂 I haven’t used Ubuntu for a while now. But I can hardly recommend the chrome browser!
      73 Tobias

  10. Rudi - ON6MI says:

    Hi Tobias,

    Took some time to solve this problem but with your fix and troubleshooting it was done in a few minutes.

    Thanks and 73’s

    Rudi, ON6MI

  11. Juan Miguel EA6NP says:

    Hi, Tobias.

    I had the same problem, with Ubuntu 10.4 and Firefox, no sound. Registring audio properties as described and removing Ice tea, now it works great.


    Juan Miguel, EA6NP

  12. Tnx for infos
    GL jose

  13. Cemal - TA2BG says:

    Hello. I had no sounds from my machine (apart from simple alert sounds) since I upgraded my Ubuntu. On the webSDR even the s-meter did not move. After following the procedure on this page, the s-meter started to move, but still no sound. Neither from webSDR nor from flash movies etc. Any suggestions?

    System>Preferences>Sound>Applications indicates that “there are no applications playing” on webSDR, the same message alternates (flickers) with “Alsa plugin” when running the flash player.

    Any pointers? Thanks in advance..

  14. Chuck Rothauser says:

    Danke! Das ist sehr gut!

    I can now hear the signals wheras before I just got the waterfalls


    —Chuck Rothauser

  15. DO9FM says:

    thx for ur tutorial, ufb with ubuntu 10.10!
    73 de DO9FM

  16. OE6RHT says:

    Thank you very much. It worked fine with my equipment (Ubuntu 10.10, Dell Latitude 2110) after minor adjustments.

    73 de OE6RHT

  17. Thank you so much. I was tearing my hair out trying to solve this. Java sound worked on my laptop, but not on my desktop, and they’re basically configured the same way, though hardware is different. It wasn’t until this article that things are working. Thank you again.

    • Hey Jim,

      happy I could help you out! I know how frustration this kind of troubleshooting can sometimes be.
      So enjoy Java Sound under Linux 🙂
      73 Tobias

  18. Grant says:

    So I finally got this working with fldigi so I decoded some RTTY from websdr using a chain of

    websdr -> pulseaudio -> jack -> fldigi

    it’d be nice if I could get java to talk straight to jack might see what I can do with that but I havn’t had much joy with the alsa jack plugin.

    • Hi Grant,
      Can you provide more details on how you got the websdr->pulseaudio->jack->fldigi chain working?


  19. bruce says:

    Problem: In Ubuntu 10.04, there’s no sound from websdr in firefox. In chrome, there is sound from the built-in sound device, but not from the default usb sound device, and there is no control of volume. All other sound sources seem to perform correctly in both browsers, including the globaltuners application, oddly enough.

    In my previous Ubuntu installation on this machine, I did manage to get Chrome working properly by using Tobias’ hints and the comment from Eldon about the quotes. If I recall correctly, firefox never worked.

  20. Dieter says:

    Problem: In Ubuntu 11.04, there’s no sound from websdr in firefox.
    All other sound sources seem to perform correctly.
    Is there any sugestions?

  21. kiri says:

    Thanks — your article helped me fix my java sound.

    I did not have to add the lines to the sound.properties. Instead I
    checked synaptic and uninstalled openjdk and iced tea. These had been
    installed on top of my sun by box.net just recently. I lost sound right
    after that! Uninstalled them, and immediately my java sound returned!

  22. somebody tested on Ubuntu 11.04 or 11.10 to install sun-Java for websdr?

    because ubuntuusers.de says sun-java is possible to install with the old repository in 10.xx,
    but this will not work on 11.xx – and will not be possible…

    any suggestions?

    • Andy66 says:

      I was to try it. no work.

    • RA3TES says:

      Hi, today I was install Ubuntu 11.04.
      Install sun-java6-jre sun-java6-plugin sun-java6-fonts
      Next I was set simbol link

      1. cd /usr/lib/mozilla/plugins
      2. sudo ln -s /usr/lib/jvm/java-6-sun/jre/lib/i386/libnpjp2.so

      All working is Good now.

  23. Used the fix on Ubuntu 10.04 32bit – worked perfectly. Just removed OpenJDK, Icedtea and installed sun-java6-jre sun-java6-plugin sun-java6-fonts. Waterfall and sound work on both Chrome and Firefox. Thanks for the great tutorial.

    On a new system with Ubuntu 10.04 64bit, the fix didn’t work. Tried the trouble shooting suggestions and it still didn’t work.

    Full details: When I first installed Ubuntu 10.04 64bit on the 64bit system, both waterfall and sound worked perfectly. Then I ran an update/upgrade, rebooted and waterfall works, but sound is gone. All of the sites on Websdr.com complain that JAVA isn’t installed. Tried the same process that had fixed the problem on the 32bit system and still doesn’t work.
    Sound works on YouTube, news videos, etc. Just doesn’t work on Websdr.com for either Firefox or Chrome.

    Any suggestions are most appreciated.


  24. marty says:

    Hello radio friends, GREAT NEWS!

    openjdk has developed far enough to run WebSDR! I just tried it.
    I am using debian, upon which ubuntu is based, and am tracking wheezy, which is the same as sid at this moment. The version of the java runtime (jre), packaged as “openjdk-6-jre” is 6b24-1.11.1-3. I did nothing special or tricky to get it going, it “just worked”. Note that the package icedtea-plugin (or equivalent) must also be installed to hook the browser to java. Please, friends, PLEASE, use open technology instead of proprietary wherever possible. The reasons are many and deep. Amateur radio is about learning and sharing information, especially in the arts of our craft. Proprietary technology can not be “taken apart” for learning like a vacuum cleaner or HF rig, open technology can, period. Let the kids learn! It is on and of your honor to do so. In some respects, the ARRL has lost their way in this regard. It is not a trivial difference.

    If you are not having fun, you are doing it wrong. Thank You, have fun!

  25. bruce says:


    I sympathize with your sentiment about open source, but the practical reality is that some important endeavors are possible only with the more substantial resources possessed by commercial entities. In this case, we have waited how long for the open java code to work reliably? In my case, on Ubuntu 10.04, I just re-installed the open java plug-in, etc., and it is still broken– waterfall, but no sound or frozen waterfall and no sound, depending on specific site visited. I don’t right now have the time to dig in to see why that has happened. So, my perspective about open-source is not quite like yours.

    Surely, it must be fair and reasonable to accept commercially developed software when it is of high quality and serves a good and useful purpose. Surely also, it must then be reasonable to allow that commercial entity a means to recoup its costs, either through direct user charges or some form advertising or other license constraints. Limiting ourselves only to that which volunteers can produce in their spare time may be noble, in a way, and highly valuable as a way to break unfair commercial monopolies, but it does not always work in the best interests of all.

  26. FYI, WebSDR worked out of the box with Linux Mint Debian Edition 64bit XFCE. I had to change nothing to start listening with FireFox 11.0.
    PS: I am a 100% Linux ham. Thanks for the great info on this site.

  27. WebSDR is working much better with Java in Linux. I’m getting the best results using Debian Sid with Sun Java 7 with the plugin and fonts. You can use Fldigi and other decoding software with Jack and a loopback interface in ALSA. Here’s a link to a way to set it up: http://www.ab9il.net/software-defined-radio/websdr-digimodes.html

  28. I am at my wits end trying to get some of the sdr remote websites to work. Some of them will work, some of them won’t, has anyone got any suggestions. Please see the you Tube video I made, you’ll see what problems I have been encountering. This problem happens on four computers in my house. Nobody else seems to be having this problem, there must be a solution. I have uninstalled and installed Java and JavaScript, but the latest version but still nothing seems to work. I’m on Windows 7 64-bit

  29. Guenter, DL7LA says:

    had to switch to Mint Maya (didn’t want a smartphone GUI) and so back to trouble again, no SDR java sound. Procedure above that worked for Ubuntu 10.04 sort of fails here: Version shows up as
    java version “1.7.0_05”
    Java(TM) SE Runtime Environment (build 1.7.0_05-b06)
    Java HotSpot(TM) Client VM (build 23.1-b03, mixed mode, sharing)
    but no sound with any of the websdrs. Guess I’ll have to wait…
    But I agree with the posters above: Sound on linux is simply a mess all the 15 years I’m with Linux now.
    mni tnx anyway

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