How to get FLDigi to work on Ubuntu 12.04


image of fldigi screen shot

fldigi receiving morse code

Its been a Ubuntu time again. Getting Fldigi to work with the sound system on Ubuntu 12.04 is finally working. Heres how I did it.

As Einstien said about radio, imagine you tread on a cats tail, the sound comes out of the cats mouth at the other end. Radio is just the same, only without the cat. We might say the same about Fldigi and Ubuntu.

The reason I found so much trouble was simply that out of the box, Ubuntu 12.04 was missing stuff that makes setting up fldigi relatively painless. If you’ve landed here for the same reason, heres what solved it for me.

1] Firstly fldigi was installed to Ubuntu 12.04 using Ubuntu’s Software Center. Simply searching for fldigi finds it.

image showing Ubuntu's Software Center successfully installed fldigi

Ubuntu's Software Center successfully installed fldigi

It may not be the most up to date version. Thats what comes of having Ubuntu manage the packing process but it shouldn’t be too old, and even so, what’s a known bug if its not affecting you? Just install it.

2] After the install is complete, you’ll find an icon under your Dash Home icon on the Ubuntu task bar up the left hand side of the screen, after you’ve typed most of fldigi in the search bar.

After fldigi launches, for first time you’ll be run through the set up wizard. The only quest we’re interested in here is what Audio settings should you use? The answer is PulseAudio.

Image of Fldigi Sound Control Panel

Fldigi Sound Control Panel

There is nothing to put in the ‘Server’ box, just leave it blank.

Stand back in amazement if you’ve got this far and its not working. This is where the missing bits come in.

3] The bit your missing on Ubuntu 12.04 is PulseAudio Volume Control

Image of Getting PulseAudio Volume Control

Getting PulseAudio Volume Control

This is what prompted me to write this article. As I searched for PulseAudio Volume Control the Ubuntu Software Center did not find it. It knows it under an abbreviation of pavc.  Now its installed, I can find it as expected in Ubuntu Software Center.

Anyhow, go ahead and install it.

What is this PulseAudio stuff?

PulseAudio provides a hardware abstraction between your hardware and software. Ugh! What does that mean? It means instead of all software having to be written to interface to many hundreds of sound cards all with their odd setups, the software is written to connect to a single sound source, and that sound source, is always the same. It worries about the odd quirks and additional features your sound card may or may not have.

PulseAudio is the current flavor of this standard interface. There are additional benefits too, such as the ability to stream music, and I presume even fldigi sound output over a network. That might be pretty cool to people who use a remote shack.

So now we know why we’ve set the sound input Device in fldigi to PulseAudio. Its nothing to do with a pulsing audio system. Its just a name given to an audio systems abstraction, and that’s how we’re going to connect fldigi to Ubuntu. Sounds all glamoursly confusing but actually it works as you’d expect it to.

If you’ve any doubt concerning if you’ve got PulseAudio running on your Ubuntu system, looking in System Monitor / Process tab you will see it running and it runs with an above normal priority, ie high priority, as normal.

4] With PulseAudio Volume Control now installed you can now get to the input and output sources that were absent from the Ubuntu 12.04 sound control panel. This is the bit that was missing, and is in effect, a rough sort of ‘software patch panel’ for sources and outputs. This is whats missing on your fldigi set up, its not doing anything cause its not getting any input.

For my fldigi input I am using online SDR. My radio looks like this:

Image of W4AX online SDR website

W4AX online SDR

And in the PulseAudio Volume Control app it looks like this:

Image of PulseAudio Volume Control Playback Tab

PulseAudio Volume Control Playback Tab

You’ll probably see just this set up on your computer now. I’m using online SDR receiver to provide an audio feed to the computer. Thats coming in via a web page, via its Java applet, and into the Alsa plug in. You don’t have to know how it works to be able to use it, thats just its ‘route’.  It is then routed to the ‘built in Audio Analogue Stereo’ as selected by the drop down list. I’m not able to capture the options I have on my computer as it won’t let me screen capture when they are shown. Your options will certainly be different anyhow, so look at your own and not mine.

I can hear digital tones from my computers speakers. Fldigi needs to know where to pick up its sound source, and its on the ‘built-in Audio Analogue Stereo’ route, so thats where we point it to. Its as easy as that. Play with your settings until it works.

If you were getting your sound source from your line in, the you’d choose the Input Devices tab and select your routing from the available drop down menu’s on the Playback tab.

If you have your Tv connected via a HDMI interface then you could route the sound to that and have fldigi pick up its source from your HDMI playback device..

If you wanted to route it to a network, or another work station then its possible to do this too.

By the way, if you have a suitable graphics card that supports Digital Theater Sound [DTS] over HDMI you’ve now, through PulseAudio Volume Control, found the place to turn that on too

Hey wait! There’s more…

Now you’ve got sound level adjustments all over the place. not only can you adjust them from within PulseAudio Volume Control but they are now appearing within the Ubuntu Sound Applet under the Applications tab. Fldigi must appear in here for its where Ubuntu is reporting what applications are currently using the Sound system.

image of ubuntu sound mixer

Ubuntu Sound Mixer

For my sins as I sit here way into the small hours of the night I am listening through Bluetooth headphones to the computer, while Morse Code chirps away and fldigi does the decoding. There is more…

Another useful app for Ubuntu that offered itself as a possible solution was the Gnome Alsa Mixer. For my entirely software set up it appeared to offer no advantage, but for people using real radios with real wires, it may be an invaluable tool.

This baby gives you access to all the other audio bits and bobs you might need for level adjustment and muting. Its worth adding to your growing collection of audio sliders.

Image of Gnome Alsa Mixer

Gnome Alsa Mixer

Its available from your Ubuntu Software Center under its name.

So there we have it. I was able to listen to music streamed over bluetooth headset while fldigi decoded on the air waves. Routing allowed stuff to go only where it was required.

The simplicity of yearning for the days when hardware was hardware, and not abstracted via software first, is akin to real tea leafs with tea pots, against tea bags.











Leave a Reply

Your email address will not be published. Required fields are marked *