The first step to OTA nirvana is to research your area. Find out which stations are transmitting DTV and where the towers are located by using AntennaWeb, the foremost authority for OTA information. You simply submit your zip code and the website will return a list of all the channels in your area. It will also list where the towers are and how far you are from them. In addition, they also provide a recommended antenna type to help you choose the correct antenna. Your success will depend on where you live and your surroundings, so this is an important step. You can also see a street level map that will help you get an idea of the tower's location, for the directionally challenged. For those who need even more help, you can head over to HDTV Magazine and use their Google maps version which provides even more information. Plus - it's fun!
Not all the DTV stations are HDTV. Some of the stations don't choose to broadcast HDTV. Yeah I know it is crazy, but true. They might choose to multi-cast SD digital channels. One station in my area actually broadcasts 4 channels which are listed on my TV as 16.1 16.2 16.3 16.4. When the station chooses to do both HDTV and multicast it usually causes degradation in picture quality, but that is another discussion.
If you want to see what HDTV programming is available in your area you can check out TitanTV. They have a program guide that makes it easy to see what OTA HDTV is available . You have to sign up to use it but it's worth it. Once you login, you can go to the TV Listings section and choose "Digital Guide (Antenna)" to see the local line up. All the HDTV programs are clearly marked, but not always 100% accurate. Check in the evening since that is when most HDTV shows are on. You can also check out local HDTV forums for your area and see what other people are doing.
Now that you know where your stations are and what you can watch, it's time to find the right antenna. As you might guess, outdoor antennas are better and should be used if possible. As a compromise you can mount an antenna in your attic. There are a few indoor antennas that work well, but to obtain the perfect reception we want, we are going to use an outdoor antenna. Now if you study the information we obtained from AntennaWeb you will see that in my area not all the channels' towers are in the same direction. The channels I want to receive are 3, 8, 10, 13, 28, 38 and 44. These are the channels with HD content that I want to watch. Lucky for me all of the channels except channel 10, are 14 miles away and in the same direction. Channel 10 is in the opposite direction and 25 miles away. That will be more difficult but we can address that with some additional equipment. The other important thing to notice about the information from AntennaWeb is that the digital channels are actually on different channels than they say they are. For example channel 10 is really channel 24. Thanks to PSIP it will show up on your TV as 10 but in reality it's channel 24. This is important because a different antenna is needed for channel 10 than for channel 24. This is because channel 10 is a VHF channel and channel 24 is a UHF channel.
Since I want to receive 2 VHF channels and 4 UHF channel from the southeast I will use a VHF/UHF combo antenna pointed in that direction. I also want to receive one UHF channel from the northwest so I will buy a separate UHF only antenna and point it northwest. I originally tried it with just one antenna but my reception of channel 10 was not perfect so I added the second one. I want to combine the two antennas so I only have to run one coax cable to my TV. If I used a regular combiner it could cause multi-path, which would hinder my reception. I could use a rotor or an A/B switch but those don't work well with TiVos since it can't control the switch or rotor. So I am going to use a JOIN-TENNA from Channel Master. They make them for every channel so you have to order the right one. I bought one for channel 24.
You can buy an antenna locally or if you are like me and like to buy things on-line you can check out Antennas Direct. They have great products and service, they will even help you pick out an antenna. Just email them and let them know your surroundings. You might also want to buy some miscellaneous supplies like a pole and wire to connect everything. You can pay someone to do this too but what fun would that be?
I mounted both my antennas on the same pole along with my JOIN-TENNA. I connected it all and used a compass to point the antennas in the appropriate direction. The exact channel direction of the tower is available on AntennaWeb. I adjusted my UHF only antenna by angling it upwards a little to improve the signal strength. After you point the antennas it is a good idea to check your signal strength with a meter in order to fine tune them. Most DTV tuners include a signal strength meter, but not all. So if yours doesn't have this feature then it will be more work. You have to check each channel to see if you can receive it and then make adjustments as needed. After each adjustment, check the other channels to make sure you don't mess the other ones up.
With my setup I receive all the channels absolutely perfect. No monthly fees, no drop outs! My total cost was about $200, plus my time. It was well worth it! I have this signal split 5 ways without a problem. Amplifiers can be used if you experience signal loss from splitting or excessively long coax runs. But remember the amplifier is used to overcome attenuation from passive devices and the length of the cable, not antenna problems.
Feel free to post any questions in the comments and good luck!