Copper Sleeve over IEC

Now I haven't had the time to audibly check what happens after installation but what I can report is that I use a portable AM radio tuned just off a station (to get static) and the polymer or plastic housings on IEC and male ends of my power cords are noisy and do exhibit less noise when the copper is in place. Not dead silent but less noise. I do have 1 power cord whose terminations are finished in aluminium and they are quiet even without the copper on them. One of my cords must not be insulated (its a 3 wire braided cord) which is noisy all along the cord itself so I don't think having copper over the ends will do much but I may be wrong.

While not yet proven by myself my opinion is that this tweak may be most effective on insulated power cords.

First off let me say I have no electrical background and I am not DIY (soldering and the like) kind of guy either so my thoughts are worth what you are paying for them...

I can see how the copper sleeve could stop airborne nasties from entering in at the IEC opening but a noisy cord like the one I have when the copper sleeve is in place isn't necessarily stopping anything from entering. It may only be acting as a shield on outbound noise from being detected. The noise traveling along the cable may be going right into the unit and the noise is less audible at the copper sleeve because its blocking it from coming out. It may still be blocking anything more from going in (which is a good thing) but it isn't necessarily blocking this noise from going into the unit. Something that may block something from entering may be just as effective blocking something from coming out as well. I still think insulated cords may be the best cord to use this tweak on.

Well thats the extent of my technical BS and I defer this to people more knowledgeable in these matters...

Yes briefly (but without listening for any audible changes) and as I said earlier I "measured" the outcome using my home made device (AM radio) that in fact when the copper sleeve is in place it reduces the noise at the terminations.

But my point is that while the copper sleeve reduces this "noise" it may not be negating it - it may only stop it from escaping and that's why I don't hear it...

Maybe my home made tool is inadequate for this exercise?

I'm all for tweaks, especially cheap ones, but if the design or desired outcome of this tweak is to stop "crap" from entering whatever component its being used on I still say the best cord is an insulated cord because if an uninsulated cord picks up anything through the cord itself it could be transmitted along the cord and into the gear and the copper sleeve would not stop this from occurring as far as I can see. If the design is to ensure that no power escapes at the terminations (although I don't know if that's possible or even a negative consequence) then I guess it works as it is quiet for my test as well.

If anyone out there has the proper tool to measure this they should try and do so with an uninsulated cord as well. If you hear noise all along the cord and then its silent at the IEC and with the copper in place it may very well be because the copper blocks you from hearing it but it doesn't prove its "killing" it off.

Maybe I am just missing the point or not expressing myself clearly enough...