AntennaWeb makes recommendations for outdoor antennas only. It does this by predicting signal levels at your address and matching them with antennas with different capabilities. We are unable to reliably predict indoor reception (and an appropriate antenna to use) because there are too many additional variables to take into account such as the thickness of the walls in your building, the construction material, the number and orientation of the walls and windows, and the indoor antenna's location with respect to the direction of the DTV station, each having a different impact on signal level for each DTV signal. However, if you have good analog TV reception on many channels with an indoor antenna then there is a good chance you will also be able to receive digital stations with an indoor antenna connected to a DTV set, set-top box or DTV converter box, but it's not guaranteed.
The first thing to try
The first thing anyone trying to get indoor reception can do is simply to try using whatever indoor antenna(s) you have available. After you've hooked the antenna to the "antenna in" jack on the digital TV or converter box, tell the TV or converter box to scan for available channels. See the device's instruction manual for instructions on how to do this. If you get all the channels you want, congratulations, you need go no further. If not, or the picture sometimes freezes or breaks up, try placing the antenna in different locations and with different orientations, looking for a location and direction that provides good reception. For digital reception, you will not see the results of your adjustments immediately. Adjust your antenna, move away from the antenna, and count to five after each position change to see if it is better. Repeat and note the positions. As a general rule, placing the antenna higher is better and placing the antenna near a window often helps.
If reception is still not satisfactory, it gets more complicated and you may need to know more to make an antenna selection. Here are some things to consider.
Look at the AntennaWeb outdoor reception predictions
Go to AntennaWeb.org, select "Choose an antenna" and enter your address, housing type, and surroundings details. When looking at the results page, select "show digital stations only". The type of antenna needed for each DTV station is listed in the left hand column. If AntennaWeb shows the colors blue or violet are needed for an outside antenna to get a particular station then it is virtually certain that an indoor antenna will not work for that station. If it shows light green it is unlikely that an indoor antenna will enable reception of that station. However, if AntennaWeb shows red, then perhaps an amplified indoor antenna will enable reception of that station, but it may be tricky. If it predicts that you will need a yellow or green antenna then there is a good chance that, depending on your specifics, the right indoor antenna will work.
The Antenna Type column also shows whether the antenna needs to be UHF or VHF for the stations you'll be watching. The actual "RF Channel" for each station is shown in the right hand column of the results page. Note that this is usually different from the channel number used to brand the station (column 4 on the AntennaWeb results page). RF Channels numbered 2-13 are VHF and channels 14 and above are UHF.
It's worth noting that some (but not all) DTV stations currently transmitting in the UHF band will be moving to VHF frequencies formerly occupied by analog stations that are being shut off. On the AntennaWeb results page these stations have two entries, one for current transmissions and one labeled "June 12, 2009 (post-transition)", which shows the new frequency allocation.
To receive all the stations in their area, most people are going to need an antenna that receives both UHF and VHF signals.
Types of indoor antennas
The traditional indoor antenna is often known as "rabbit ears" and may have two rods or "elements" that can be pulled out and positioned at different angles. This type is intended to receive all VHF channels. An indoor antenna with an element in the shape of a loop or a "bowtie" shape is intended to receive UHF channels. Sometimes an antenna may have both types of elements in one unit and these are known as combination VHF/UHF antennas. These antennas will work for DTV reception in some locations but in others a more complex design may be needed.
While we can't recommend specific models, if you are shopping for a new indoor antenna there are a few things to look out for. The most important is to make sure that the antenna you are considering covers all the VHF and UHF RF channels you wish to receive. Labels such as "Designed for HDTV" tell you little about the performance of the antenna, and it is worth asking what UHF and VHF channels it is designed to receive and whether it is an omni-directional or a directional antenna.
Some indoor antennas receive signals more or less equally from all directions, these are known as "omni-directional" and it doesn't matter much which direction they point in. These are best suited for high signal strength areas and have the advantage that they don't need to be adjusted for direction. However, they are not good at pulling in low-level signals and do not reject unwanted signals from other directions, so they can't be used in difficult reception conditions.
There are other antennas that focus their reception capability in one specific direction while ignoring signals coming from other directions. They are known as "directional antennas". These typically have a row of parallel elements, or a wire mesh type of grid with a loop or bowtie in front. When TV signals come into your home they can bounce off the walls, creating reflections. To the TV these extra reflected versions of the signal appear to be interference, and they make reception more difficult. A directional indoor antenna can help capture one of these reflections while ignoring the others, making reception easier. Many of these antennas are designed for UHF only and do not work well, or at all, on VHF. This is because UHF antennas are smaller in size, so it's much easier to create a directional indoor UHF antenna than it is to create a directional indoor VHF antenna. If your analog picture had a "ghosted" image in it, that's an indication of signal reflections. With the directional type of antenna you may have to adjust the antenna position for best reception on each channel.
Some indoor antennas include a built-in amplifier. This boosts the weak signal so it is receivable in areas of low signal strength, where a simple non-amplified antenna may not be satisfactory. If you are considering an amplified indoor antenna, make sure it receives both UHF and VHF signals if the DTV stations you want are in both bands.
Use your analog TV reception experience to understand challenges you might face with DTV
If you're still having a hard time receiving a DTV station you may be able to get a general idea as to why this might be happening by analyzing the analog picture from the same station. If you are currently receiving analog signals on an indoor antenna, what those signals look like sometimes can provide information to help you determine if an indoor antenna will work for digital reception. If your analog pictures are crisp, clear and never wiggle, then you have a good signal, and your current antenna will probably work – if it can get the frequency band the DTV station is using (UHF or VHF).
If your analog picture has some or many tiny spots that change quickly all the time (called "snow") that is an indication of a weak signal condition. This implies that something is blocking the signal at that location. For example, the antenna is in a below ground basement (AntennaWeb assumes your outdoor antenna is 20 feet above ground for single story buildings and 30 feet above ground for multi-story buildings, unless you input a specific antenna height under the "options" section). The more material (especially earth) in the path from the DTV station to the antenna the less signal gets through. DTV reception in a below ground basement with an indoor antenna is unlikely. If there is only a little snow on the analog picture of the station you're trying to receive then an electronically amplified antenna may be the best solution.
Squiggly bands or diagonal lines that move through an analog TV picture generally indicate that there is an interfering signal. This can be from a wireless device, a computer, a game console, or an appliance in your house or, if you live in an apartment, in a nearby apartment. If the interference to analog reception is worse on low numbered analog channels (VHF channels 2-13) and not present on high numbered analog channels (UHF channels at 14 and above), and the DTV signal you're trying to receive is in the VHF band then digital reception may be more difficult. The opposite is also true, if the interference to analog reception is present in the UHF band and not present in the VHF band then DTV reception in the UHF band may be more difficult.
If the only problem with your analog reception for a particular station was ghosted images there's a good chance you'll be able to get DTV reception for that station. DTV receivers are generally good at recovering one signal from multiple reflections unless the number and position of the repeated images are changing a lot.
Smart Antennas
The latest technology that enables reception without constant adjustment of the antenna is called "smart antenna" technology. This requires the matching of a smart antenna, which has specially designed built-in electronics, with a DTV set or set-top box that is programmed to automatically control the smart antenna. Some combinations of smart antennas and DTV set-top boxes with smart antenna connectors work very well together and enable reception much better than any other solution; other combinations do not work at all. Obtaining smart antennas can be difficult because most retailers don't carry them yet.