Interesting article on part 15

"It seems that social distancing has made unlicensed Part 15 radio a bit more popular. “Part 15” refers to the part of the US broadcast regulations that cover unintended transmissions and radio frequency interference. Essentially, this means tiny radio signals whose transmission can’t be avoided or are negligible. It also covers tiny radio transmitters, like the kind that fit into your cars 12-volt socket to broadcast your smartphone into your dashboard FM receiver, or, less commonly, AM transmitters used by real estate agents to create “talking houses” for drivers by.

With restrictions and good sense preventing many churches from holding in-person services, many apparently have looked to Part 15 broadcasting to transmit sermons to parishioners parked in their car. With a broadcast range of several hundred feet on the AM dial, it’s a way to bring people together for a shared experience while keeping them safely apart. All without requiring attendees to have smartphones or use up their mobile bandwidth (assuming a church is somewhere with reliable wireless coverage).

"While a few hundred feet or broadcast range is probably sufficient for a large percentage of worship houses, I can imagine it’s still not enough for some larger mega-churches, which might want to reach hundreds of cars in acres of parking lots."