There are several ways to install SvxLink:
SvxLink was developed by Tobias (SM0SVX) under Fedora Linux. It should be easy to install under Fedora, because binary packages are available. Since it was developed under Fedora, it is also best tested under this distribution.
SvxLink has a few dependent packages. Most of them should already be installed on a normal Linux workstation. Qtel needs X/Qt but the SvxLink server is a pure console application.
Note: For ALSA based systems (like Fedora >=2) the Alsa OSS emulation is used for sound input and output. However, there is a bug in the emulation layer that causes SvxLink and Qtel not to work. To work around this bug the environment variable ASYNC_AUDIO_NOTRIGGER was introduced.
This is set to 1 by default to work around this bug, as most modern Linux distributions use ALSA by default. If you get problems with the audio output, set this variable to 0. For the SvxLink server, you can do this in the /etc/sysconfig/svxlink startup script.
For Qtel, you can set this variable manually on the command line, in a startup script, or in the shell login script. The following instructions assume that the bash is the default shell for most Linux distributions:
Or on the command line:
ASYNC_AUDIO_NOTRIGGER=0 qtel &
The environment settings are lost each time you log out of the system. For this reason, you should add the above export line to the „.bash_profile“ file located in your home directory. Setting this variable is not necessarily necessary and may cause SvxLink or Qtel to malfunction. Therefore, only set this variable if you have audio problems!
Note: Close all other applications that access the sound card and run at the same time as SvxLink/Qtel. If another program has already opened the sound interface, SvxLink will wait until this application is closed. Especially in case of problems with SvxLink, e.g. „hanging up“ and other sound problems, check if a sound server like artsd or others is running. Be that as it may, this problem is not important because most distributions use the ALSA sound layer.
If you only want to use Qtel, first read the „Audio Level Settings“ section and then the Qtel documentation.
In order to operate the SvxLink server, certain hardware is required to connect the computer to the radio. At the moment I am using an interface from Aleks, S54S, which completely separates the PC from the radio using optocouplers and transformers.
For a long time I used a simple, non-isolated interface which also worked. But this way I destroyed a soundcard.
WB0RXX/Tim developed a circuit which he uses together with SvxLink. You can have a look at this circuit here.
The interfaces developed for Echolink can also be used for SvxLink. Just have a look at the Echolink website. I haven’t tested any of them, so I can’t give any guarantee on function. Please give me a short feedback if these interfaces work together with SvxLink or not.
Adjust audio level
Neither Qtel nor the SvxLink server offer the possibility to set the audio level. The levels must be set using aumix, kmix, alsamixer or any other external application.
Locate the controls needed to adjust the levels. The LF output level is defined by the Pcm and Vol knobs, and the input level by the „Capture“ knob (sometimes called IGain), but not the Mic or line-in knob! The last two are used to adjust the level for monitoring the two inputs.
Set both to level 0. Select either the Mic or line-in input.
The Pcm Vol and Mic/Input controls should be set to 50% at sthqa. Now adjust the levels according to the following instructions.
To set the levels for Qtel, connect to the *ECHOTEST* server. This EchoLinkserver will return everything it has received. Shortly after the connection has been established, you will hear a greeting. Now use the Pcm and Vol controls to set the level to an acceptable level. Press the PTT button, speak something and then hear what is being said. Adjust the level of the Capture control until you are satisfied.
To set the audio levels for the Svxlink server, first set the configuration variable PEAK_METER to 1 in the Receiver Configuration section of svxlin.conf.
Start the svxlink and press *# on your keyboard. This command causes SvxLink to identify itself. The number sign # is only necessary if the * command is entered directly on the keyboard. If you want to do this by radio, send a * and the following closing of the squelch causes the same effect. Do this several times and set the controls for Pcm and Vol to the highest possible values without overdriving.
To adjust the audio input level, open the receiver’s squelch so that SvxLink receives the receiver’s noise.
Increase the audio input level until overdrive messages appear on the console. Now reduce the level again until these messages are no longer output. If these messages do not appear at all, the overall audio level is too low. In this case you should try to solve the problem on the analog input side or change the PREAMP configuration variable in the Receiver Configuration section accordingly.
Now activate the parrot module (parrot) by pressing 1# on your keyboard. Now send something with another radio and hear whether the signal being played back is of good quality. Send some DTMF characters and see if they are decoded properly. If not, change the audio levels again.
Test all 16 characters: 0-9, *, #, A, B, C, D.
As a rule for all settings, never set the controls to values above 90%. With most soundcards, distortion occurs when the level is too high. If the audio level is not sufficient, change the value of the configuration variable PREAMP in the configuration file.