1. Try this link
[Link: homeautomationnet.com]2. The filter would go on the offender
3. Anything in the house can cause these problems. The most common offenders seem to be tv's, av gear, power strips, and computers although there are others.
Go around you house and unplug any of these items and then try you system, you can then start to reconnect things and see what causes the most problems, sometimes a coupler/repeater will need to be installed in the circuit panel. If you search this forum you will find tons of info on the subject.