Yes, the law says that you must be able to accept a certain amount of interference - without damage.
(But it doesn't specifically state that you must be "unaffected" by it.........)
The problem with "simply measuring the RF emissions" is that it often fails to tell you what you want to know.
Noise has a huge variety of different characteristics.... as does the effect it has on various equipment.
You can limit the overall amount of noise something puts out, but that won't tell you if a tiny bit of noise at a particular frequency will affect another piece of gear that happens to be sensitive to that frequency.
The other thing to remember is that a lot of current equipment
INTENTIONALLY puts out RF noise - in huge quantities.
For example, if your cell phone didn't blast out enough RF power to be picked up for miles, it wouldn't work....
Likewise, your WiFi router, and all your other WiFi devices, radiate power - because that's how they talk to each other.
And, even though it's well shielded, your microwave oven is a 1000 watt radio transmitter.... so a little of that is always going to leak out when it's running.
And, any device with a brush motor - like an electric drill, or many fans - also emits broad-band RF noise (the original radio transmitter was simply a spark jumping between two wires).
In order for those measurements to be meaningful, you would have to identify the particular frequencies your device is sensitive to, see what's there, and then identify where any noise that's there is coming from.
(If you put that RF meter next to your cell phone and press "talk", you'll peg the meter, but that won't tell you if your cell phone is interfering with any particular device.)
And, once you did, odds are that you'd find that nobody was breaking the rules anyway.
Because of this, a meter can be very effective for tracking down what particular device is interfering with what other particular device, but "just eliminating all the interference" is a non-starter.
These days, it's downright difficult to find
ANY frequency range that isn't packed with transmissions already.
(And the ones that most devices carefully avoid are that way because they've already been promised to other devices - which use them.)
Luckily, these days, most equipment has been successfully designed to be relatively insensitive to the more common types of interference.
For example, if your TV made buzzy noises every time someone used a cell phone within a mile, regardless of blame or legal regulations, people would eventually start avoiding that brand.
Likewise, if every cell phone in the house stopped working when you turned your TV on, that would be noticed pretty quickly as well.
(And, since you aren't going to get people to stop using their cell phones, it would be up to you to not buy that brand of TV.... or, perhaps, to add a line filter and see if it helps.)
Luckily, it isn't really that difficult to shield most equipment from RF noise..... and most power supplies already have plenty of filtering.
(maybe I should rephrase that...... it can be very difficult, but that's a problem for the manufacturer, and not you.)
I should note that, while circuitry like phono preamps may be especially sensitive to RF noise, there are also simple ways to reduce that sensitivity.
(For example, a few ferrite beads on the input leads will effectively block most RF interference, while having no effect whatsoever on the audio.)
The bottom line is that consumer equipment is SUPPOSED TO BE designed to work in a typical consumer home situation.
I should mention at this point that, at least so far, I have
NOT received a single phone call complaining about the power supply in an XPA Gen3 amp interfering with any other device.
(And, if this were at all a real problem, we'd certainly have heard about it by now.)
I believe such law ALSO states something about a piece of equipment have to ACCEPT such interference.
RFI can crawl up / down grounds as easily as any other admitance.
But I tend to agree that it is somewhat of an overstated problem......
Please link affordable 'RF Meter'.
