<p><b>Leadsign Portable Digital TV Antenna is a passive antenna.</b> It works best for TV towers 0-35 miles away. If you are from TV tower over 35miles away,you may add a <b>Signal Amplifier </b>to amplify the range and boost signals. </p><p><b>Before buying,you may do: </b></p><p>1) Pls check if your TV has a builtin ATSC tuner for receiving over-the-air broadcasts,if NO,pls get a digital-to-analog converter box; </p><p>2) Pls check what channels are available,the distance to the broadcast tower and the signal strength in your area by visiting"dtv.gov/maps" or "tvfool" or "AntennaWeb".</p><p><b>Choose the Right TV Antenna</b></p><p>The type of antenna needed at a specific location may vary depending on geographic location,the height at which the antenna is used and other local factors such as nearby buildings,trees,terrain or home construction</p><p>25mile antenna for TV towers 10-20miles away.</p><p>35mile antenna for TV towers 25-35miles away.</p><p>50mile antenna for TV tower over 35miles away.</p><p>Outdoor antenna as powerful as possible if surrounded by hills,trees,metal or high buildings</p><p><b>Reception Tips:</b></p><p>1.Antennas typically need to be oriented or "aimed" to get the best signal from the desired station. DTV reception can often be improved just by changing the location of your current antenna,even as little as a few inches</p><p>2.<b> </b>Remember to do another channel scan after you have adjusted your antenna </p><p>3.<b>If you are near a station's broadcast tower, reception of that station,as well as other stations,can be impeded by strong signal "overload." If you suspect this to be the case,you may want to remove any signal amplifiers you may have or try to install an "attenuator" to reduce the amount of signal coming to your converter box or DTV.</b></p><p>4.Actual signal strength may vary based on a variety of factors(mentioned above).Your signal strength may be significantly lower in extremely