This is funny 'cause I always put ferrite cores on my equipment, including the IR cables to the MRF and MSC. My wife thought they were snake oil until I pointed out that all our IBM Thinkpad power supplies had them. Then I sent her a link to an online article that explains induction and how they work and she nodded off. When she woke up, she agreed they worked and politely asked me not to bore her in that particular way again. ;-)

Basically, they stop a long wire from being used as an antenna, either to transmit or receive. So, I put them near the component on all power cables (to stop the component from transmitting) and near the MSC to stop them from being used as an antenna. The more times you can wrap the cable, the more effective they are. This is an exponential equation, so twice is *a lot* better than once. Just make sure you wrap them in the same direction.

They also help organize cables, which is always a plus.

And no, they aren't the perfect solution to every problem. But, they're cheap, and effective, so why not? If nothing else, use them instead of velcro ties on the last leg of the run. If the client / guest / wife asks about them, you can show off a little on your knowledge of electronic components and inductive circuit transmission theory.

Sean