[arm-allstar] QRM from Node

Doug Crompton wa3dsp at gmail.com
Thu Jan 10 00:03:39 EST 2019


 This is undoubtedly coming from the wall wart power supply which is a
switcher. If you want to eliminate the noise you could run the node from
your shack 12V power supply. Just make a cable up, make sure the polarity
is right, and it should go away. Ferrites may work but I doubt as good as
eliminating the switcher altogether. Unfortunately this is a plague that
effects hams and SWL's that we did not have many years ago. Stuff coming in
from China that does not pass FCC requirements and probably was never

*73 Doug*


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

On Wed, Jan 9, 2019 at 11:50 PM "George via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Greetings,
> For some reason it seems that my yellow box node is causing quite a buzz
> on my Perseus SDR receiver and other HF radios tonight.  As soon as I
> unplug the node, the vast majority if the qrm goes away.  The sound is a
> pulsing buzz noise.
> The next step is to add some ferrites to the various lines to the node
> (power and antenna).  I am really curious what made tonight different.
> QRM in this neighbor hood is a huge problem.  Have others noticed qrm from
> their nodes?
>  Regards,
> George, NJ3H
> Redmond, Oregon USADMR Node:  3141315Allstar Node:  49246Echolink Node
> NJ3H-L:  3135
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