[CQ-Contest] DSP units with great noise reduction

Jim Brown k9yc at audiosystemsgroup.com
Thu Oct 22 14:19:01 EDT 2020

On 10/22/2020 7:36 AM, Michael Walker wrote:
> John
> I have to say that 80% of the noise that impacted me on the low bands (and
> even 2M) was in my house.  

Yes, the stuff in our own homes is often our worst enemy!

> I spent a few days going around with a Handheld that had AM on it and
> narrowing it down.  I replaced about a dozen wall chargers (Garmin and
> Apple being the worst).

I have boxes of vintage linear supplies that I use to replace the 
switching supplies that come with almost anything we buy.
> I added Mix 31 and 43 chokes to both ends of every feedline depending on
> the frequency.  This also includes DC power cables.  I ended up buying
> about 100 of each and I have used most of them.

#43 cores are a poor choice for the HF bands.
> It was the Yankee Contest Clipper Club document on choking that got me to
> dig in further into my own home.  

Here's my tutorial on the topic. It shows how to identify noise sources 
and kill them. It ran in NCJ several years ago.

73, Jim K9YC

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