Pagers use the "side bands" on commercial or public FM broadcast stations.
That is why pagers work in places cell phones hven't got a hope in hell of working!
Here in South Australia, MMM-FM, a community radio station, sell their side band for "Muzak".
Emergency services like our Country Fire Service use pagers, as do the Ambo's.
FM radio transmitters don't mess around power wise, they transmit in the mega watt level.