[arm-allstar] Asterisk - Hum

[Terry Bethlehem]

Run a ground wire to each device, daisy chaining them together ground wise.
Then run that to a known good ground.

On Dec 13, 2017 5:56 PM, Eric Smyder via arm-allstar <
arm-allstar at hamvoip.org> wrote:

> Thanks for answering my inquiry, David.
>
> The Pi3 is powered by the supply that came with it.  Is that supply
> considered stable and clean enough?
>
> The BF-888s is battery-powered.  The interface is the homebrew interface
> following the USB FOB Simple Modification right in the DB shell.
> https://hamvoip.org/hamradio/usb_fob_simple_modification/
>
> The W3HZU repeater runs the DMK URI interface off the IBM PC in the video.
>
> How would one begin to attack the problem if it is a ground loop?
>
> thanks,
>
> Eric
> N3FIX
>
>
> On Wed, Dec 13, 2017 at 10:27 PM, David McGough <kb4fxc at inttek.net> wrote:
>
> >
> > Hi Eric,
> >
> > You don't mention what type of interfaces you're using--like URI's,
> > homebrew fobs, etc.???
> >
> > The noise heard on the HamVoIP system sounds like noise from a switching
> > power supply and/or ground loop in the audio path.
> >
> > How are you powering the RPi3??  And, similarly for the BF888??
> >
> >
> > 73, David KB4FXC
> >
> >
> > On Wed, 13 Dec 2017, "Eric Smyder via arm-allstar" wrote:
> >
> > > Hello all:
> > >
> > > I've been experimenting with HAMVOIP, on a Pi3 at the home QTH with a
> > > BF-888s as my radio.  It is a remarkably good system and easy to
> > > configure.  However, I'm having an issue.  It is actually the same
> issue
> > I
> > > noticed on the W3HZU 6 meter repeater.
> > >
> > > The video links below exemplifies the issue.  When transmitting
> directly
> > > from the repeater with the hand-mic the repeater sounds great.  When I
> > > trigger the AllStarLink from Asterisk, or when the node makes an
> > > announcement or identifies, there is a distinct tone or hum.  I get the
> > > same thing on my Pi 3 at the house if I key the transmitter and speak
> > into
> > > the BF-888s.  It seems to be coming through the computer or being
> picked
> > up
> > > somewhere in the connections to the URI.  I have taken measures to
> shield
> > > the wiring between the radio and the URI, but the hum is still there.
> > >
> > > At W3HZU 6m AllStarLink
> > > https://photos.app.goo.gl/OtJn3aK2ZRCd6cPs2
> > >
> > > At the home QTH using the Pi3, where the hum is more noticeable.
> > > https://photos.app.goo.gl/XsUC4on5t04LH6CS2
> > >
> > > Has anyone else noticed this and is there something I can do about it?
> > >
> > > Thanks,
> > >
> > > Eric
> > > N3FIX
> > > _______________________________________________
> > >
> > > arm-allstar mailing list
> > > arm-allstar at hamvoip.org
> > > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> > >
> > > Visit the BBB and RPi2/3 web page - http://hamvoip.org
> > >
> >
> >
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>
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>
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>