Actually, the stations do a lot more than preach. Much of their broadcast time is devoted to community, education and health programs. Marimba music is the most popular type of music. Ranchera and tropical music are also heard, but are not as popular among the Mayans. The latter two types of music are more common on Guatemalan AM stations which broadcast for the Ladinos.
Some programming is in Spanish, but most is in Indian languages.
Although the Mayan languages are phonetically very different from Spanish, it is easy to be fooled into thinking they're Spanish. A lot of Spanish words have been borrowed, especially for modern ideas and religious terminology. As Guatemala is only a short ionospheric hop away from North America, reception can be quite clear and strong sometimes, especially in mid-winter. Also, Guatemalan stations tend to be interference free, as higher powered stations in South America have already faded out with their local sunrise and the Guatemalans are more than a match for any Asians on nearby frequencies. Let's take a look at Guatemala's provincial SW stations, starting with the Roman Catholic ones.