[450] Link back up

John Foege john.foege at gmail.com
Tue Nov 3 06:21:17 UTC 2015

The link is back up for testing.

RF input side audio has been *significantly* improved.

TX audio out from internet still sounds great playing through the
integrated broadcom soundcard.

I believe the PTT line issue is solved now. It seemed to be RF getting in
via the BUSY/RECEIVING data line coming out of the radio back to the
raspberry pi. A partial fix was to wrap this line 10-20 around a ferrite
core. This seemed to solved the instability issue about 80% of the time. As
an added measure, I placed a pull-up resistor on the PTT line on the raspi
side from +5V board input to the PTT line output on the ULN2003A driver.
This should help to force the PTT line to a determinate state and should
solve the intermittent PTT line issue 100%.

We tried moving both input and output audio streams to the attached USB
sound card, and this worked, however the USB sound card had noticeably
inferior output audio (read clock noise), and thus we switched back to the
raspi's integrated broadcom sound card for output audio, while retaining
the attached USB sound card for input audio (from the radio back to the

Next steps will be:

1) Complete backup of SDCARD image

2) Backup of svxlink conf files (git or svn repo)

3) Extensive testing of link in current configuration

4) Download and compile latest svxlink binaries and start w/ a simple
vanilla conf w/ no extraneous bullshit

5) Documentation

6) Stacked loop install and testing

Anything I miss? Any input, comments, feedback, etc?

What calls need to be added that are not currently in there? Or calls that
need to be modified?

I will follow w/ most current access list.
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