If you have stations of interest grouped together so that you can aim one antenna and get them all, consider yourself fortunate. Most OTA TV viewers have to find a way to receive signals that arrive from two or more directions.
Traditional rotators have been a common solution but a source of frustration for the viewers who don't have control of antenna aim. Some TVs and set top tuners and converters lack the ability to add channels manually and also may lack the ability to add channels through scanning. Tuners with this limitation require a full rescan each time the antenna is rotated... quite time consuming and frustrating when used with an antenna needing to be rotated.
A/B switches can be used to select between two antenna leads. There are manual and remote controlled products to choose from. This solution will be problematic for tuners lacking manual-add and add-scan functionality.
In some cases a tuned antenna combiner may be an option. The Channel Master Join-Tenna may still be available through Warren Electronics
who still stock a limited selection of UHF and VHF product. The tuned antenna combiner makes the adjacent channels unusable. For example, if you used an CH-9 Join-Tenna to add a lone signal to the main antenna feed, CH-8 and CH-10 would be blocked by the filters in the combiner. When many UHF signals are involved, it's less likely that a combination of tuned combiners would provide a satisfactory solution. http://www.tinlee.com/
may be able to provide a workable solution, their website does not list pricing information but invites inquiry from individual customers.
In addition to the standard definition DTV converters on the market, there are several full HD resolution tuners such as the Channel Master CM7400
as well as a tuner by Centronix
which offer HDMI interface to your monitor or AV receiver. The Winegard RC-1010
is an HD capable tuner but it lacks HDMI output. Western Digital
have products worth considering also.
So here's the alternative
... Most TVs, analog and digital, have video and audio inputs, many new digital TVs have HDMI, some even have multiple inputs. You can opt to place a SD or HD capable tuner next to the TV, connecting it to the TV through the extra input port. Now the TV has a second tuner which can be used to terminate a secondary antenna aimed as needed. With a multiple input TV, this can be expanded to include a third or even forth antenna.