The K3 has isolation transformers on LINE IN/OUT. You don't need to add any more. I assume you're using the term "ground-loop problems" in the generic [and somewhat archaic] sense. Make sure that you're not using the shield of any of the cables [RF or AF] as the bond between your component's chassis' or enclosures. They should all be directly bonded together. If isolating the shields with external isolation transformers fixes the noise, that's a huge clue.

Finding the "chassis" on laptops can be a problem. The hold-down nuts on DB or DE connectors are often [but not always] one place to get it. Unfortunately, those can be hard to find on some new laptops.

In stubborn cases, I'm told it sometimes helps if all the power cords connect to the same green wire too although I've never had to go that far.


Fred K6DGW
-Sparks NV DM09dn

- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016

On 9/19/2016 9:24 AM, dw wrote:

Any way, I've been experiencing ground-loop noise from my PC.
I've tried three different isolation transformers and they all work, but
with significant signal loss from the PC.
Does anyone have a suggestion?

N1BBR :-]

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