Over-the-air (OTA) HDTV is a big hit these days. High definition television is one on those rare services that comes in the highest quality when it is free of charge. You can watch amazing 1080i resolution broadcasts over the air for free, and get better quality for the same channels than through a paid satellite DTV subscription. All you need is a high definition TV set with a built-in HDTV tuner and an off-air HDTV antenna.
Do you know what HDTV antenna is? If you do, forget it immediately. There is no such thing.
Do you know what a regular antenna is? Antenna is a piece of metal designed to resonate at a specific frequency and to be responsive over a range of frequencies. TV antennas are designed to work either in the range of Ultra High Frequencies (UHF), Very High Frequencies (VHF) or both. Any station transmitting within an antenna bandwidth, i.e. the VHF/UHF frequency range, can be picked up by the antenna and transferred to the TV set.
All television broadcasts, digital and analog, high definition and standard definition, take place in the VHF and the UHF bands. What makes a signal to be HD is its content, the way a signal is modulated, and not the carrier frequency it is transmitted on. On the contrary, for antenna only the frequency matters.
There is nothing specific about a TV antenna that is used to receive HD signals. Your antenna doesn't really care whether the signal is high definition or not. It has absolutely no idea what the signal resolution is, or whether the signal is analog or digital. The antenna doesn't care that you are receiving HDTV as it doesn't care whether you are watching Fox News or NBC channel.
Okay, may be I oversimplify the matters. There is a little bit more to it. Besides the bandwidth there are few additional electrical and spatial properties a good antenna must have. Most notably, directivity, high front-to-back (F/B) ratio and low-noise amplification in case the antenna comes with an amplifier. Does anything of these matter from the analog vs. HDTV reception perspective?
There is a wrong, yet widespread belief that you need more powerful antenna in terms of directivity and amplification in order to receive digital television. I don't know where the hell this belief comes from, cause the situation is exactly the opposite. HDTV is much more noise immune than the analog television and can produce high quality video at significantly lower signal-to-noise ratios. So in principle, if analog and digital stations transmitted at the same power, you would need less antenna gain and could tolerate higher noise levels to receive error free digital TV. In reality, networks exploit the inherent noise immunity of the digital TV to transmit HDTV signal at reduced power. All in all, antennas with similar directivity/gain properties should receive analog and digital broadcasts equally well.
The other important specification, F/B ratio, has to do with the antenna ability to receive a signal coming towards its front from the direction the antenna points to, and to reject a signal coming from behind. In the presence of tall buildings or other reflective structures, the signal travels from the towers to the antenna by multiple paths, each path arrives at a different time instant. The multipath phenomena is responsible for a "ghost" creation in analog television. A desirable property of the antenna is to receive a single strongest replica of the signal coming through the strongest path and to reject the weak replicas. The higher F/B ratio is, the better is multipath rejection (ghost suppression). Without going into technical details, we must say that HDTV signal is a bit more sensitive to multipath phenomena cause it has slightly larger bandwidth. Such a difference in multipath sensitivity is negligibly small. Most directional, old fashioned and cheap TV antenna has F/B ratio good enough to handle HDTV signal. If an antenna can handle an analog signal, it can handle a digital signal as well.
You may ask why there are so many "HDTV antennas" on the market. HDTV is a fancy buzzword. HDTV is cool. It sells. HDTV antenna is nothing but a hype. Don't be fooled by the ubiquitous ads promoting HDTV antennas and HDTV optimized antennas. These antennas are HDTV antennas indeed, but to no lesser extent they are "SDTV antennas", "EDTV antennas" and "NTSC antennas". Let's say all of them are just TV antennas.
When choosing an antenna for HDTV, check the really important parameters such as directivity, gain, F/B ratio. These specifications are important for reception of both, digital and analog broadcasts. Consult our step-by-step HDTV antenna selection guide and read antenna reviews. The HDTV optimization is probably the least important factor you should take into account.