In the end, it was cheaper and convenient to just add local TV channels to my Internet service.
It could be that you are just too far from the towers.
This tool might help - an indoor antenna should be able to pick up any of the ‘green’ signals, and depending on construction and location in the building, may pick up yellow. (I’d want a signal booster to try anything yellow, and it might be needed for green). Conditions would have to be close to ideal to pick up anything brown.
https://transition.fcc.gov/mb/engineering/dtvmaps/
Antenna web also has a tool. They specifically disclaim reliability for indoor antennas, but again, anything green and probably at least some blue should work indoors with a powered signal booster (either built in or in-line).
http://www.antennaweb.org/Address
Unfortunately, Radio Shack used to be the go-to place for equipment.