One of my housemates is a ham radio nut; I can confirm that even after isolating his power lines, he still sees broad spectrum interference when my roadster is charging.
I'll bet it's a lot worse in my 1.5 than the newer roadsters, as I'm guessing at least some of the interference is from re-using parts of the main motor as part of the charging process.
Well, ok then! Let's try this again.
As another Ham Radio Nut, I did some experimenting with my Roadster. Sorry, but it's a 2.0, so as mentioned, your results may be different.
I doubt the issue is coming from the motor, as it's (hopefully!) not spinning during the charge cycle. With my car charging on 120v, I scanned the region around the PEM from 300mhz to 436mhz. The radio is a Kenwood TH-F6, set to USB for best sensitivity, but with the squelch set just high enough to get rid of most of the ambient junk. I found 13 spikes in the background noise, all except for two of them were still there with the car unplugged and asleep. I presume they are from CATV leakage, or the PC or Internet router in the adjacent room. The two exceptions were at 334.8 mhz and 375.0 mhz. Both returned when the car was awakened (just opened the passenger door, not charging), and went away again the instant the car returned to sleep. Both needed the radio antenna to be fairly close to the PEM; they weren't strong enough to break squelch a few feet away. None were specifically associated with charging, so I'm not seeing anything that would explain what you are seeing.
I'm curious about your car's noise being described as "broad spectrum". The RF noise generated by my car is definitely not broad; it's pretty narrow, which is consistent with being generated by digital circuitry. Broad spectrum noise is more often mechanically created, for example, arcing contacts in motors. Given that it's not the main motor, it could be one of the fan or pump motors, though I've never seen such a source be strong enough to desense an external receiver.
Another possibility is that there's a broken, or loose and oxidized, ground connection. Since the car itself has a plastic shell, the usual non-ignition sources of RF noise in cars don't apply. You might ask the service center to look around for any missing or loose screws in/around the PEM, especially in the high voltage section.
The only other place I can think of would be the charging circuitry itself. I presume the internal charger is essentially a big switching power supply. If poorly designed and filtered, they can be notorious for creating noise. But it's not usually that high up in RF frequency (below 30 mhz mostly), and usually there's a periodicity to the noise that's easy to spot by ear. What happens when you listen on an external AM radio? What does it sound like when you tune around?
I've asked some other ham contacts for advice, and will pass on what they suggest.
