In article , Glenn Richards wrote:
In a conversation I had with a friend, we determined that power
cables are good at carrying low frequencies, and poor at carrying
higher frequencies. So RFI picked up at the substation won't make
it to your house, but interference sources in your house will cause
RFI to reach your kit.
How do you determine the electrical properties of cables by
conversation?

By applying known principles of engineering.

Applying them to what?

The losses at high frequencies are significantly higher in 2.5mm mains
wiring cable than screened co-ax, if you don't believe me try running a
composite video signal down mains cable (rather than 75ohm co-ax) and
see how far you get.

I think you have unwittingly confirmed that it is not "conversation" that
determines the properties of cables (or anything else), but testing.

It's like saying "how can you determine that an Audi Quattro is going to
go around a hairpin bend at 100mph faster than a Ford Fiesta", for example.

It is indeed, and the answer is the same. No amount of conversation will
determine the abilities of motor cars without some sort of practical test.

Unless you can explain otherwise......

Rod.