Assuming the change does not get delayed (see this NY Times article), in about a month, the analog TV signal from TV stations will be turned off.
If you have an old TV connected to an outside antenna or rabbit ears, you will need to make some changes to prepare for the change.
I have written several artricles on this subject and have completed an installation of a converter box on a newer TV with a coax cable connection, and a VERY old TV with twin screw antenna connection.
Read my Digital TV Conversion articles. Don’t be left without a TV signal!