Excerpt from RF Venue blog:
As a part of the clearing of the 600 MHz band, the FCC started repacking TV stations, mostly channel 38 and above back in November of 2018. The move would include almost 1000 stations in the USA and Canada. The scheduled completion date (Phase 10) was July 3 2020. However, with the Covid-19 pandemic, the FCC granted some additional time starting with Phase 9 of the move. For those in Canada there will also be a Phase 11 to follow.
So what this means is if you are in one of the areas shown on the map below your may have wireless microphone or in-ear monitor systems that have stopped working due to wholesale changes to your local spectrum conditions.