[arm-allstar] Asterisk - Hum

[Doug Crompton]

Eric,

 I guess I will throw my 2 cents in as it seems everyone else has. Did you
ever answer the question about "does it vary when you move around" ? When
using local nodes like the 888 with a short antenna and another handheld
talking to it in close proximity there are often phasing relationships that
can cause what appears to be hum modulation on the signal. This can happen
in both directions but sometimes only one. The answer is eith to identify
the areas that do this and try to stay away from them or improve and/or
move the antenna. The hum caused by this can be just in the background to
so loud that it is very annoying and often competes with voice audio. There
can also be an additional problem if you have other RF going on in the area
and simultaneously transmitting. This usually only occurs in close quarter
operations like a local node within a home.

If I assume this is not the problem then it should be easy to identify at
what point the hum is being introduced. You can disconnect the power
and/or  control lines from the FOB to the radio and try to track down at
what point it is being introduced. However remember that disconnecting an
888 or any radio that uses cos=usb in simpleusb-tune-menu will cause cos to
go true and issue a key signal out over the network to anyone you are
connect to. Best to do test with local connections or to someone at another
node that know what you are doing.

Email is also exhaustively slow and sometimes not very intuitive. If you
can't seem to get anywhere with this I would be glad to talk to you on the
phone about it or on my Philly hub - 27225 - eastern time and I am around
on and off from about 11 AM to late at night.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*


On Wed, Dec 13, 2017 at 4:59 PM, "Eric Smyder via arm-allstar" <
arm-allstar at hamvoip.org> 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
>