Hi all,
I have a high physical and emotional dependency on The Beatles channel, #18 on XM radio. I pity my fellow drivers if someone were take that away from me. Just last week, I listened to very important hurricane recovery news broadcasting on AM radio. Both of these are now enabled on my $6,000 Nissan Leaf.
A 2.315 Ghz antenna for satellite radio is tiny. They put them in very small receivers, just as they do WiFi antennas that operate nearby at 2.4Ghz. Your mobile phone has a 2.4Ghz antenna printed inside. While the ideal location is on the roof of the vehicle, the Model 3 has a barren dashboard where to mount it.
It would be reaching to say that car manufacturers are removing AM receivers because electric motors interfere with the signal. Europe has very strict RF interference compliance tests and a car that emits that level of noise will likely not pass. Tesla, especially, that combines motor and controller into a single (nearly Faraday caged) unit should not have this issue.
Again, my cheap (and electric) Nissan Leaf has clear AM reception. My guess is that they don't like AM receivers because they need the largest of antennas (the lower the frequency, the larger the antenna). That said, they put a large defroster on the back window. It wouldn't look too off to put the antenna there, too.
Regards,
JR