[arm-allstar] low levell constant whine

[Doug Crompton]

Alan,

 Need to know more about your setup. What FOB? It sounds like a grounding
or positioning problem. I had the same thing using a DMK-URI. Both low
voltage fans and switching power supplies produce high frequency noise. The
FOB is an excellent pickup for this noise if it is placed near the noise
source. Low voltage fans can be decoupled from introducing the noise on the
power line with a small resistor - say 15 ohms and a electrolytic cap 100uf
or higher on the source side to ground.


*73 Doug*

*WA3DSP*

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

On Mon, Nov 12, 2018 at 1:23 PM "Alan Matthews via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Hi Guys
>
> I have heard various allstar nodes generating a constant low level whining
> noise. My repeater has worked fine for a number of weeks but suddenly has
> started to make this noise.
>
> can anyone advise what it is, and if possible what might cause it and even
> better how to cure it.
>
> many thanks
> regards alan
>
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