For those interested here's my coverage with a Decade MS-100 operating at BETS-1 field strength in the area of Toronto where I live.
Have an arrow pointing to my house.
Holy Moly! What the spacing between those houses?
The houses are close together on this street. Lots of houses on the block.
in the main circle the distance between the two streets on the block where my house is is 660 ft. so I am getting out 300 to 400 ft each way except for that dip to the south. The small circle on the right is the top floors of a retirement home.
This is with a receiver like a Sangean, GE super, Grundig field 450, HI FI tuner etc.
Houses are about 6 to 7 ft apart. Across the street is townhouses.
Look at street view of 55 Rory Rd and you can see up close. You will see my Chev. Cobalt in the driveway.
You put that transmitter outside in a waterproof box on a pole 10-20 Ft and it would fly. FM loves to be open so I'm quite sure you'd get good coverage.
If you need to get audio up there you can use a Bluetooth receiver and transmitter set. There are some that have two antennas on them and they have a nice range of clear signal.
Yes that would be nice. I think that's what Artisan did for a few years and I think he got power and audio to it with long cables.