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<body class='hmmessage'><div dir='ltr'><font style="" color="#000000" face="Tahoma,sans-serif">Randy,<br><br> 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...<br><br>Are you using 1.2.1 code? Have you changed the startup delay time which defaults to 30 seconds?<br><br>If this is just hum what frequency is it? 60 cycles, 120 cycles or higher?<br><br>Is it happening in both directions TX and RX?<br><br>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.<br id="FontBreak"></font><br><font style="" face="Tahoma,sans-serif">Happy New Year!</font><br><br><b><font style="font-size:16pt;" size="4">73 Doug</font><font style="font-size:16pt;" size="4"><br></font><font style="font-size:16pt;" size="4">WA3DSP</font><font style="font-size:16pt;" size="4"><br></font><font style="font-size:16pt;" size="4">http://www.crompton.com/hamradio</font></b><font style="font-size:16pt;" size="4"><br></font><br><br><div><hr id="stopSpelling">Date: Thu, 1 Jan 2015 02:42:25 -0500<br>From: randy@neals.ca<br>To: arm-allstar@hamvoip.org<br>Subject: [arm-allstar] BBB URI USB-HUB Distorted Audio<br><br><div dir="ltr"><br>I've been experiencing a distorted audio problem while setting up a BBB with powered USB-HUB, DMK URI, and USB Keyboard.<br><br>The audio distortion is noticeable on audio from the node. (transmit audio)<br>To eliminate/isolate the issue I swapped out the URI for a SYBA USB Audio FOB and PC speakers.<br>Still the same background hum/distortion. So that eliminated RF interference, ground loops, the URI and the radio.<br><br>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)<br><br>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.<br><br>My next troubleshooting step is to swap out the keyboard, and then swap out the USB HUB.<br><br>The USB Hub I'm using is an AmazonBasics 4 Port USB 3.0 Hub with 5V/2.5A power adapter<ul style="color:rgb(148,148,148);padding:0px;font-family:Arial,sans-serif;font-size:13px;line-height:19px;"><li style="list-style:disc;word-wrap:break-word;"><span style="color:rgb(17,17,17);">Package 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 Manual</span></li><li style="list-style:disc;word-wrap:break-word;"><span style="color:rgb(17,17,17);">Compatible with USB 3.0 and backwards compatible with USB 2.0</span></li><li style="list-style:disc;word-wrap:break-word;"><span style="color:rgb(17,17,17);">Support Low speed (1.5 Mbps)/ Full speed (12 Mbps)/High speed (480 Mbps)/ Super speed (5 Gbps)</span></li><li style="list-style:disc;word-wrap:break-word;"><span style="color:rgb(17,17,17);">Support auto switching between self-power and buspower mode</span></li></ul><br><br></div>
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