HDTV indicates the number of lines that are shown by the TV. (HD means that at least 720 lines can be displayed in a given picture.) To receive OTA signals, you need an ATSC tuner (digital) of sufficient power (with a clear path to the transmitter) these days. The RCA D52W20 was released in 2002 and only has an NTSC (analog tuner). You will need a digital-to-analog converter to receive OTA TV (unless any low power analog stations remain in your area).
Please note that the basic digital-to-analog converters that were available with the government coupon back in 2009 were SD (480i lines of pixels used) units. HD d-t-a converters exist but are more expensive.
I hope this helps.
(the phrase "digital antenna" is meaningless; check with tvfool.com
for the direction of local transmitters. TVfool.com will give more information on the type of antenna (indoor, outdoor, amplifier) that you will need to receive channels in your area. Antennaweb assumes an external antenna but is very conservative in the stations that it will indicate that you can receive. Antennas are given a color rating based on how far away the transmitter can be to get a watchable signal. Since digital signals are either enough for the tuner to interpret or you get a "no signal" message, you often need a stronger signal than was needed to receive a watchable analog channel.)