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Date: Fri, 16 Jun 2017 20:46:36 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <15ca21dc75e-1e15-bcda@webprd-m105.mail.aol.com> <0f9558b4-457d-a395-58c9-7f9be3393cdd@sky.com> <4767d79f-2bf6-d838-bfd4-3e78102d6f5d@abelian.org>
In-Reply-To: <4767d79f-2bf6-d838-bfd4-3e78102d6f5d@abelian.org>
Subject: Re: LF: Octo-soundcard for the Raspi
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Hi Paul,

I took a brand new SD card for the Raspi, installed the latest Raspbian 
version. Also installed the soundcard and vlfrx tools. It works!
...mounted a USB stick, enabled ssh access, installed a RAM-disk (32 MB).

On another PC running vlfrx tools i managed to blow into a microphone 
connected to soundcard1 and listen to the sound on soundcard0. 
Fantastic! :-)

So i'm learning in small steps...

73, Stefan


Am 15.06.2017 09:10, schrieb Paul Nicholson:
>
> The Octo is working quite nicely with vlfrx-tools.
>
> Getting less than a uS timing jitter on a good clean PPS.
>
> The card actually delivers 8 input channels but chans 7 and
> 8 are silent.
>
> To get the thing running, update your RPi firmware with
>
>  rpi-update
>
> and then edit /boot/config.txt to add the line
>
>  dtoverlay=audioinjector-addons
>
> and reboot.  Then,
>
>  cat /proc/asound/cards
>
> should report the interface is present as card 0.
>
> A suitable vtcard command is
>
>  vtcard -d hw:0,0 -r96000 -b32 -c8 -L /run/vtcard.log -Bv @raw
>
> -B puts it into background.  I put the log file into ramdisk
> /run, otherwise on my RPi at least, it produces card overruns
> when vtcard occasionally blocks when writing its log file to
> the SD.
>
> Spectrum seems to be quite clean.   The card runs reliably,
> I've had no errors or overruns in 5 days of operation.
>
> vtcard, vttime, and a single channel vtsid use about 25%
> of a quad-core RPi capacity, so 3 cores are idle on average.
>
> vttime should have six channels specified for input, ie
>
>  vttime -m ppsbase+,w=auto -c6 -L vttime.log -Bv @raw:1,2,3,4,5,6 @timed
>
> where -c6 tells vttime that the PPS is on chan 6.   If you try to
> start it with all 8 channels, then vttime can't quite keep up
> and it gives regular timing breaks as @raw overruns.
>
> Measuring a 9765.625 Hz reference from a GPSDO through the Octo,
> I'm seeing about a degree of phase jitter which isn't bad.
> Plenty good enough for amateur radio coherent reception.
> Monitoring for certain types of SID need a little better than that.
>
> Conclusion: worked well but no longer available.
>
> -- 
> Paul Nicholson
> -- 
>