For over-the-air TV, there is usually* no difference between a "digital antenna" and I suppose the marketing opposite would be an "analog antenna." They both pick up radio waves the same. The digital or analog decoding is performed in your TV or digital converter box, not the antenna. Calling an antenna "digital" is usually a marketing ploy to get you to throw away your old antenna and buy a new one.
It's like marketing "digital headphones." How many of us have digital ears? Can you hear a stream of ones and zeros, or does that just sound like white noise? Headphones reproduce the
sound from a stereo, whether it comes from a digital MP3 or CD, or analog Vinyl albums, cassettes or 8-tracks. Antennas capture radio waves from the air on specific bands, and send them to the tuner circuits.
What is important in a small OTA antenna in fringe areas is to
select one with a preamplifier at the antenna, before you start suffering cable losses. An indoor amp at the TV end may do no good recovering a weak signal already lost in the cable. Antennas with a preamp will have a small "power injector" or control box that goes onto the cable near the TV to send DC power up the cable to the preamp at the antenna.
An antenna marketed as a "digital antenna" is much more likely, but not guaranteed to have a preamp in it. Standard RV OTA antennas are available either with or without a preamp.
*Note: During the transition period from analog to digital, stations actually used two seperate transmitters on different TV channels. Most of the vacant channels used for the digital version were in UHF (Channel 14 and up).
So some "digital antennas" left over from the transition period are tuned for UHF only, figuring they will hit most of the channels without people noticing that VHF Channels 2 to 13, which require more metal to gather the waves, don't come in quite as well.
On the day analog died (except for a few very low-power specialty stations), each big station had to choose to either stay on the new digital frequency (but with the old analog channel ID on the digital stream), or turn off the new channel and install a digital transmitter on their old frequency. Most stations did not look back. Only one station in our market went back to its actual analog frequency.
CBS 6.1 went back from UHF to VHF Channel 6
ABC 10.1 stayed on Channel 26
NBC 13.1 stayed on VHF Channel 12
PBS 17.1 stayed on Channel 34
FOX 23.1 stayed on VHF Channel 7
So a UHF-Only antenna would not get NBC well at any time. It would get the old FOX analog and the temporary CBS digital on UHF before the turn-off date. After the turn-off, the only major networks still on UHF here are ABC and PBS.
The bottom line is, get an antenna with a preamp (or buy a preamp "bullet" to insert in the coax at the antenna terminals. And make sure it is rated for both VHF and UHF, not just UHF.
To find the actual OTA (as well as virtual) frequencies used in any area, go to
http://www.antennaweb.org and enter the local zip code.