[arm-allstar] hum on my allstar nodes

[Doug Crompton]

The "RF" hum is caused by some odd phasing relationship and/or RF overload
at the site. When you think of it you rarely transmit RF that close to the
destination most of the time. We have found that distance and selecting
locations that are best are about the only thing you can do in this case.
It usually only happens when you are very close to the node. If this is
your problem the only thing you can do is change locations of equipment or
antennas and distance from your node.

*73 Doug, WA3DSP*
*http://wa3dsp.org <http://wa3dsp.org>*

On Sun, Apr 26, 2020 at 11:57 AM "Chris Smart via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Thanks Doug.
>
>
> What is typically the source of this hum? Wall-wart type power supplies?
>
> 73
>
>
> Chris
>
>
>
> On 4/26/2020 10:46 AM, "Doug Crompton via ARM-allstar" wrote:
> > Hum on local RF nodes is a common problem when transmitting TO your node.
> > It is usually because you are too close to your node. If the hum stops
> when
> > you move to another location, sometimes just a foot or two one way or the
> > other then that is probably the problem. It happens more often when using
> > antennas that are mounted on the node itself. One way to get rid of it is
> > to use those small mag mount antennas that have 10-15 feet of coax and
> get
> > it away from your operating position or use an outdoor antenna. Other
> than
> > that there is no filtering or other way to eliminate it. If the hum is
> > constant at any location even walking hundreds of feet away then it is
> not
> > this phenomenon.
> >
> > *73 Doug, WA3DSP*
> > *http://wa3dsp.org <http://wa3dsp.org>*
> >
> >
> >
> > On Sun, Apr 26, 2020 at 4:08 AM "Jed Barton via ARM-allstar" <
> > arm-allstar at hamvoip.org> wrote:
> >
> >> Hey guys,
> >>
> >> So i'm sure i'm not the only 1 with this problem. I've got all my
> >> allstar pies plugged in.  They each have their own power supply. It's
> >> the typical wall wart.  They all produce a nice little hum that's just
> >> annoying.
> >> I'm sure a lot of you guys have delt with this.  You hear it on the
> >> node transmitter such as the Shari.  Any ideas for getting rid of it,
> >> or reducing it?
> >>
> >> Cheers,
> >>
> >> Jed
> >> _______________________________________________
> >>
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> >>
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> >>
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