RF cable around ring?

[+Philsan]

I had a problem with the RF coaxial cable of my VCS and I have discovered a spare Atari computer RF cable to use.

I have found that the cable is rolled up around a ring inside a box (see picture).

Why? This cable works perfectly.

Edited March 1, 2009 by Philsan

[nathanallan]

iirc, that's a toroid core that helps guard against signal interference.

[+poobah]

it basically creates an inductor with a large resistance to high frequency currents (which are actually converted to heat in the ferrite core).

 

The upshot is that it filters out high frequency noise.