Nobody said:
And one "saturating" signal source (common by the way) is a cheezy
wallwart. (or "outlet-mounted power supply with a DC power cord).
It's just a nasty side-effect of badly designed and/or built switching
regulators, but also a fail-mode on 'good" ones.
It really doesn't matter what device it powers (or charges). I've seen
bad wallwarts on everything from baby-bottle warmers to military
ECM/ECCM gear.
I spent 10+ years investigating interference problems for a public
utility, and there's a "virtual dumpster" full of the bad ones I've
found. (think 40' container).
Most are easy, they are so bad that they 'take out' the obvious stuff
like broadcast radio and TV as soon as they are plugged in, or if they
are in a 'hard charge' mode.
I don't even want to start on the hard-to-find ones.
FWIW, I've had to replace 4 of the ~10 wallwarts in my own house over
the last 3 years over interference issues. 2 of those required using
and/or modifying aftermarket units as the vendors repeatedly failed to
provide good replacements.
This is just opinion.
As an aside on Bluetooth... it's been one of the better RF protocols
regarding outside interference, but bad Bluetooth devices can kill BT
for hundreds of feet. I had a cheap ($23) BT headset that killed off
*any* other BT device in the house if the battery even slightly dropped
from full-charge.
The only strange one I've had here, is an Antec ATX power supply
pumping so much noise back into the AC line, it causes sync to drop
on the ADSL modem.
All my wall warts (and I have a "Christmas tree" of them), have been
relatively well behaved. It's a good thing I don't use Wifi or BT, so
I'll never know if they're interfering
The only Wifi gadget I've got, is Wifi in the laptop, but there's no
Wifi on the router for it to use. I do everything with wires here.
I like the reliability of wired mice and keyboards, and Ethernet cables.
Paul