Tuesday, November 20, 2012

Revisits

I haven't blogged in a while.

I have been messing with the low cost Raspberry Pi computer for some off-network ham  VOIP linking.


(The left-most (white FOB) is a CM-108 chipset; the Virtual 7.1 ch sound one is a CM-119, the LogiLink UA0053, and an unknown one.)


Adding a USB sound device is easy (as it doesn't have an on-board audio input), configuring the mixer and getting the sample rate stuff right so it works and sounds decent has been aggravating thus far.

I don't understand why it has to have custom configuration's defined/setup in .asoundrc, for various sample rates.  I am used to command line tools like play and record and sox just working with whatever I am trying to play.  

If you are in the same boat as me, these threads seems to offer some clues:
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=28&t=10848

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=38&t=20866 

For us hams you may want to check out these places to congregate:
http://groups.yahoo.com/group/Raspberry_Pi_4-Ham_RADIO/ 

http://amateurradiopi.com/forum/

And if someone comes up with a nice step by step how-to on the audio thing to share, please let me know!

This radioreference post seems pretty detailed.  Here the thread author is adding a USB sound device to provide an input for use with DSD.  However I wasn't successful with this either.



In the advent of cheap RF hardware, I have also been messing with GNU radio.  Alas, seems I don't really have a fast enough computer to run it well.  I was hoping a 3 GHz, P4 with be enough.



Never-the-less, while I seem to lack new topics, there are some older ones that perhaps someone in your local club can contribute to:

NWR SAME software decoder - Looks like someone has added EAS / SAME support to multimon

HSMM BDA -

P25 Software Repeater -



Misc:

http://forum.xda-developers.com/showthread.php?t=1982149 - App to enable all wireless channels on Android. This might be useful for amateur networks.

And lastly, am I the only one that is disgusted with the series of QST articles on the variations of PL-259 installations?