[arm-allstar] BBB URI USB-HUB Distorted Audio

[Doug Crompton]

Randy,

  I guess my first question is it truly hum or distortion? You said distortion and I think what you need to nail down is it a digital or analog problem.  Some questions...

Are you using 1.2.1 code? Have you changed the startup delay time which defaults to 30 seconds?

If this is just hum what frequency is it? 60 cycles, 120 cycles or higher?

Is it happening in both directions TX and RX?

A lot of people use the DMK and cheap USB fobs and this is the first I have heard of any analog problems especially when there is not readio connected and no potential ground loops.
Happy New Year!

73 Doug
WA3DSP
http://www.crompton.com/hamradio


Date: Thu, 1 Jan 2015 02:42:25 -0500
From: randy at neals.ca
To: arm-allstar at hamvoip.org
Subject: [arm-allstar] BBB URI USB-HUB Distorted Audio


I've been experiencing a distorted audio problem while setting up a BBB with powered USB-HUB, DMK URI, and USB Keyboard.

The audio distortion is noticeable on audio from the node. (transmit audio)
To eliminate/isolate the issue I swapped out the URI for a SYBA USB Audio FOB and PC speakers.
Still the same background hum/distortion. So that eliminated RF interference, ground loops, the URI and the radio.

Through further elimination, I have identified that when my USB keyboard is connected to the USB HUB, the hum/distortion is louder. (URI through USB HUB to BBB, no Keyboard)

And then have compared the audio when not using a USB hub at all, and I think there is a further improvement in audio, although not as major as when the keyboard is /is-not connected.

My next troubleshooting step is to swap out the keyboard, and then swap out the USB HUB.

The USB Hub I'm using is an AmazonBasics 4 Port USB 3.0 Hub with 5V/2.5A power adapterPackage includes: 1 USB 3.0 4 Port Hub / 1 5V/2.5A Power Adapter / 1 built in 10 inch USB 3.0 cable / 1 Owner's ManualCompatible with USB 3.0 and backwards compatible with USB 2.0Support Low speed (1.5 Mbps)/ Full speed (12 Mbps)/High speed (480 Mbps)/ Super speed (5 Gbps)Support auto switching between self-power and buspower mode



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