There must be something that limits the effectiveness of this thing
I'm all for clear guidelines / rules being set up. If for no other reason than to reduce the size of the questionnaire players have to submit to GMs to know how that specific instance of the game world works.
Without it, it is pretty much left up to each table to work out on their own. Most of the GMs I've ever experienced handwave / ignore Noise. Of course, that was 5e, where Noise couldn't stop a Meta Link from making a call...
Here is a Noise survival guide to hold people over until / if official rules are handed down:
Now, I'm not talking about the mechanic, it obviously exists. I mean Noise itself isn't any "real" thing in the game world. It is
heavily abstracted, and based on a bunch of (in-world) mechanical assumptions that don't make a whole lot of sense, so you can't expect Noise to make a whole lot of sense in itself.
The sooner you can make peace with that, the less headaches you will have.
- It's purpose is respectable, however it's existence is questionable
The primary purpose is to make things "interesting" (in the Chinese curse kind of way) for Tech characters. It is very much like Background Count for Mages in that sense. "What's Background Count? It isn't in the Core Book..." Exactly my point.

(It is one of the legs of the MagicRun complaint.)
If you are a character the will likely run into Noise frequently, it is often very easy to negate it most of the time. Or, at least, come close to negating it.
It only really ever plays a part on those
next to the character that will likely run into it frequently.
- It is a level of complication that some GMs won't even bother with
While it is okay to theorycraft and try to figure out how it works in RAW, it may never come up in games. Depends on the GM, and the characters at the table. If the group doesn't have any Deckers/Riggers (quite common in 5e), there isn't any real need for it except as a plot point.
If the group does have a Techie, if it becomes clear that Noise will never really impact them, then it will likely get sidelined as a rule not worth the effort.
All of this is a YMMV topic, of course.
But im still not sure how i would handle someone trying to locate a nearby active jamming field for the purpose of avoiding or investigating it.
Ehh... That is a much more difficult question. It would depend heavily on the character in question and what mode they are in. I would think it would be much easier for someone in VR to "spot" a distortion field caused be a Jammer...
Mechanically, I would suggest have the most likely individual make a Matrix Perception check, with a Threshold of 6 - Jammer Rating (or equivalent) to notice the distortion.
I mean, if you are using it as a plot point, there isn't any real need to make it more complex than that.