There are all kinds of RF interference issues. Years ago, when I worked HVAC/R service, my boss built a brand new shop, a few hundred feet from an electrical contractor. One Monday he practically accused me of leaving the shop "wide open." I told him I hadn't been anywhere near the shop all weekend. Turns out the two-way radio system next door was arbitrarily opening the shop door. We fixed that QUICK. Unplugged the receiver, and just used the indoor wired button.
As a former RADAR tech in the Navy, and having been a radio amateur for a large chunk of my life, as well as having worked a few years for a Motorola service shop, the "stuff" that can cause issues is truly amazing. One thing, EG, that is a BIG gotcha is known as an "external mixer." Think crystal radio. ANYTHING that causes what is known as a "non linear device" can mix RF signals and cause undesired outputs. Have you heard of the underground / spy / "foxhole" radios in WWII? Back then razor blades were not stainless, they were STEEL, which RUSTS. Take a safety pin, and a rusty blade, and if you are "lucky" you have an RF detector. A mixer.
A rendition of a "foxhole radio:"
Now what this translates to in some of what I've been involved with is this: Looks galvanized fence parts, gutters and even roofing that is two pieces can form an external detector, IE "foxhole radio."
A great example of this is that if you go up to a radio site with lots of transmitters online, all you need do to see this in action is to tune in a "weaker" station on your scanner. Now take two screwdrivers, cross the blades so they touch, and rub them together. You will HEAR the scratching in the radio!!!! This is because 2 or more transmitters are "mixing" in the screwdrivers, your "foxhole radio detector" and are producing RF noise, "mixing products"
This same thing can happen in a miriad of ways. LED diodes!!!! HEY!!! They are DIODES. "Crystal radio!!!!". If you are say, a CB'er or amateur, and troubled with TV interference, look no further than a mast mounted amplifier for the TV, FULL of components which can be mixers......detectors.
I guess the point is....this ain't easy, sometimes.
The bane of my existence nowadays is modern digital "stuff" and "switching" (switch mode) power supplies, and I JUST RECENTLY discovered that AC powered LED lamps (some) generate RF noise and hash.