I joined two antennas. One high gain lava-230 and a phillips/Zenith local range aerial. The lava was pre-amped and the Philips was not. Joined the lava into a power passing 2 way splitter and joined the other antenna to the blocked side. It worked but I lost one local channel because the amplified antenna saw a stronger signal and cancelled out that channel on the local antenna. Re-did the install. Two antennas and two cable runs to a A/B switch. When i want WBGU dt-27 from 58 miles away I flip to the B side and it is working great. I just had to try combining to test. And it failed for me. The A/B switch I can live with. By the way the pre-amp is a Winegard HD-269 on the Lava antenna. Also the zip is 46825.