[arm-allstar] Kerchunk - OS Sound

[David McGough]

Hi James,

I'm not sure exactly what your hardware wiring is and I'm assuming
you're running the simpleusb channel driver??

I suspect that you're not adequately terminating the COS input to the USB
adapter. A typical solution is to use a pull-up or pull-down resistor to
insure that COS is pulled toward the inactive state. The resistor value is 
usually not too sensitive, some value between 10K to 22K being typically 
what I use (whatever I find first!).

So, if you've got carrierfrom=usbinvert in simpleusb.conf, COS is active 
low (when pulled to ground), and you would use a pull-up resistor to the 
logic-high (positive voltage) level, helping to insure that COS goes 
inactive when the radio is turned off, disconnected or if any digital/RF 
"noise" is floating around on the COS line.

And, if carrierfrom=usb, the scenario is reversed, use a pull-down 
resistor to ground.


73, David KB4FXC





On Fri, 10 Feb 2017, "James Hatmaker via arm-allstar" wrote:

> Doug,
> To answer your question, I am viewing the Kerchunk count in asterisk's
> itself using the "rpt stats $NODEID" command.
> one of the lines:
> 
> Kerchunks today..................................: 0
> 
> The counter resets each night at midnight.
> 
> When testing, I can disconnect/power off the radio, and connect the allstar
> node (call it node A)  to one of our other nodes (call it node B), and we
> will hear a kerchunk on the node B (and any other Allstar nodes that are
> linked.
> This will show up in the "rpt stats $NODEID" on node A in the Kerchunks
> today.  On all the other nodes it does not show up as a kerchunk but just a
> valid "KeyUp"
> 
> I can  reliably re-produce by running dmesg on the Raspberry Pi node A.
> So, basically after running "dmesg" on the command line of the Pi for node A
> we would see:
> Kerchunks today..................................: 1
> 
> 
> 
> On the connected/distant allstar node (node B), we would here a
> kerchunk/keyup the stats would have something
> Identifier state.................................: CLEAN
> Kerchunks today..................................: 0
> Kerchunks since system initialization............: 0
> Keyups today.....................................: 0
> Keyups since system initialization...............: 367
> 
> The Kerchunk count on node B will still be 0 (where it was incremented on
> node A).
> A valid Keyup would have been detected on node B.
> 
> The fact that I can reproduce this with the radio on node A powered off and
> by running a command on the system was what was leading me down the path
> that maybe there was a system sound that was being detected by the USB
> sound device.  (and not from RF being received by the radio).
> 
> Of course this may just be a rabbit hole that could just easily be "fixed"
> by rebuilding with the new version.  However, it is in my nature to figure
> out the root cause. I have specifically kept this node around because I
> wanted to figure out what was causing the anomaly.
> 
> 73
> 
> James
> KC7LHV
> 
> 
>