Foxx said:LQB said:That's what I did - get the meter first, then the filters if you need them. The meter runs about $150 and measures the noise spectrum in 1-140KHz (where most of the noise is). Due to the cost, cost-sharing with friends and family is the way to go. You want to test all sockets (115V). I was amazed to find some really high values - some off-scale (>2000)
Are the filters for a whole house or for individual sockets? I'm imagining that they must hook in somewhere for the whole house, possibly in the circuit breaker box.
The filters are for individual sockets. I looked into a whole house version and there are a lot of con artists out there ready to take your money. If you really wanted to go that route you would want to install it grid-side at the transformer, get the power co involved, and pay thousands for the filter. David Stetzer designed and builds the socket unit, meter, and power strip (great for all that noisy computer stuff) that has 2 filters built in.
His site is http://www.stetzerelectric.com/store/stetzerizer-filter/ but you can get the stuff cheaper if you look around (like http://www.blockemf.com/catalog/product_info.php?products_id=4866&gclid=CIec16iS8rACFc2A7QodCXhuwA). The Stetzer folks will match the price if you ask. I think these are sold in the UK as well.
The way you do this is to hit the worst sockets first with a filter and move on. The goal is to get down to 30 GS units (2000 is max scale). What determines a "bad" socket depends on your wiring geometry/impedance at the noise frequencies. No way to predict - just measure. Then check periodically (as the noise can change) and tweek if necessary.