[App_rpt-users] USB fob choppy/stuttering audio

[Marshall Oldham]

Rob, 

 

Based on your comments about the telemetry "not sounding choppy when listening to it over the
phone."

 

It could be that RF from your transmitter is getting into your sound fob.  Do you have a
transmitter hooked up to the USB sound fob? 

 

As a test, disable your transmitter and use clip leads to connect a PC amplified computer
speaker to your TX audio line and see if you still have choppy audio. 

 

If you do  NOT have choppy audio with the amplified speaker, this surely points to some type of
RF getting into your sound fob. 

 

Hope this helps.

 

73 

 

Marshall - ke6pcv  

 

 

 

From: App_rpt-users [mailto:app_rpt-users-bounces at lists.allstarlink.org] On Behalf Of Rob Noll
Sent: Sunday, March 31, 2019 7:26 AM
To: app_rpt-users at lists.allstarlink.org
Subject: [App_rpt-users] USB fob choppy/stuttering audio

 

Good morning all,

 

I'm trying to set up an AllStar node using a USB fob based on the CM119 chip.  I'm having
issues with choppy/stuttering audio, particularly on telemetry.  It's bad enough that it
renders the CW ID meaningless.

My original thought was lack of CPU power, but I have tried it on a Raspberry Pi 2, Pi 3, and
several virtual machines on a quad-core PC with identical results.  Also, the choppiness is NOT
as bad when using the full USB driver instead of SimpleUSB, which I believe conclusively rules
out CPU power.

I've also tried a powered USB hub, thinking that the USB device was not receiving enough power,
with no improvement.

I've used the Android mobile app to connect to the node, and the telemetry does not seem to be
choppy when listening to it over the app.  While I need to do some more testing to say this
conclusively, I do believe at this point that my issue is narrowed down to the USB fob itself
and/or the specific audio stream being sent to the device.

I'm currently searching for a way to alter the sample rate that ASL is sending the audio to the
device in.

Has anyone experienced this, and does anyone have any suggestions?

 

Thanks and 73,

 

Rob, WX1N

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