https://www.marcelpost.com/wiki/index.php?action=history&feed=atom&title=Aprs-soundmodemAprs-soundmodem - Revision history2026-05-17T04:59:06ZRevision history for this page on the wikiMediaWiki 1.39.17https://www.marcelpost.com/wiki/index.php?title=Aprs-soundmodem&diff=1574&oldid=prevAdmin at 03:22, 4 August 20142014-08-04T03:22:03Z<p></p>
<p><b>New page</b></p><div>This page describes the modifications and setup required to get a linux box (a Raspberry Pi) working as an aprs iGate.<br />
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==sound levels==<br />
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Alsa is used for the sound system. To check the proper input levels use the command:<br />
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<code><br />
arecord -Dhw:0 -c2 -d 0 -fdat /dev/null -vvv<br />
</code><br />
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This will show a rolling output of the recorded sound levels. More alsa options: [[alsa]]<br />
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http://forums.whirlpool.net.au/archive/1853993<br />
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Alsamixer and aumix can both set the sound levels and the following settings are near optimal for me:<br />
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Alsamixer:<br />
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PCM Capture: Line<br />
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Line capture input level: 70<br />
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Everything else in alsamixer can be set to mute<br />
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Btw, if F4 doesn't toggle the recording view, try the TAB key<br />
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Aumix:<br />
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Recording device: Line<br />
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Pcm level: 100%<br />
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All other levels (including line, as it's line-out) can be set to zero<br />
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== test soundmodem output ==<br />
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a program called netcat (or ncat) can be used to send single character to the soundmodem ip address (if using MKISS).<br />
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syntax:<br />
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<code><br />
netcat -u 44.10.10.1 5000<br />
</code><br />
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when issuing the above command user input is expected. Simply type a letter, followed by <ENTER> and the soundmodem should start making AX.25 noises.</div>Admin