Great tips Dood, especially with so many transmitters and receivers using one master oscillator for all bands. If that drifts then everything is off.
I do remember the analog TV frequency standards, someone wrote a construction article for one in possibly Popular Electronics, with a loop antenna that picked up the 15.75 khz horizontal frequency from a television, which was supposed to be sourced from a rubidium standard somewhere, like at the TV networks.
With faster circuits now, timing seems to be even more important, so new transceivers should have GPS sync. New AM broadcast transmitters do, and a broadcast pro was calling for broadcasters to sync in phase lock with GPS so that beats would be less objectionable.
Boomer