This little map is based on my location near 81st and Memorial. (You can generate a version for your location on this page at fcc.gov).
As you can see from the labels I added, almost all the network stations and their subchannels are located to the east-southeast near Coweta. They are 12-16 miles from us.
Unamplified indoor antennas should be adequate for most stations within 30 miles or so. KRSC-35 (now KRSU) north of Claremore is just under 30 miles from us.
But there is a caveat. Where you place an antenna within your house can be critical for best results, and requires experimentation to find the best spot(s).
There was exactly one spot in our theater room within range of one antenna’s cable that worked well for almost all the stations. It was in the middle of the wall, east-facing, and as high on the wall as it could get. Surprisingly, this wall is an interior one.
In the den, I taped a flat antenna directly to the inside of an east-facing window.
Be prepared for surprises when you move your antenna around, because the interior structure of your house (especially wiring and metal), and exterior buildings and trees affect reception by creating radio wave reflections and blank areas.
The best placement may be counter-intuitive. It might be flat on a table, or facing a “wrong” direction.
Some placements are forgiving. Some have problems with particular stations. In our den, the chimney is between the antenna and the channel 44 transmitter to the southwest, which blocks it pretty effectively.
The map above can help make sense of why some spots work and why some do not.