One thing to keep in mind, guys, is that AM signals in that part of the spectrum (low frequency) are prone to propagation characteristics much differently than FM broadcast and Satellite radio. The weather, humidity, and ionosphere all contribute to how far a signal will bounce or if it will get absorbed. Signals this low in frequency typically follow groundwaves (ie, follow the earth's curvature) in the day. At night, the waves will travel via skywave and groundwave.
FM Broadcast is 100 times higher in frequncy (VHF) and a different modulation. These signals are almost purely line of site because the wavelength is much smaller.
Point being, that AM broadcast station propagation is much less stable and certain months I can pick up stations in Ft. Worth Texas from my car in Louisville, some months I can barely make the trip to Cincinnati! If you start paying attention to when you can and can't pick up certain stations, you might notice a pattern based on weather, solar cycles, temperature, etc.
Not saying that the window tint isn't a factor, but propagation can play tricks too.
