A few months ago I installed an antenna system in Round Lake beach Illinois. It required a Large Winegard U/V antenna and a Winegard pre- amp. I connected my Samsung STB and it did program itself. Channel 3 or digital WBBM would not lock in. In fact the signal would dissappear then bounce to the center of the signal scale. I did view the digital UHF channels for about three minutes then the screen went black. No audio and no video display and the STB menu controls would not function. The green signal light would remain solid and green. I unplgged the STB for one hour and it came on again and locked up again. I unplugged the box reaimed the antenna at Milwaukee stations . Pluged the STB and it loaded itself and then it shut down again. My questions are could the pre-amp be to much for the STB to handle? And I did notice about 1500 feet away was a power sub station . This has been a problem for analog channel 2 AND CHANNEL 5. Also the sub station interference would creep into the high band VHF channels as well . When I got my STB back to Ft. Wayne it has been working well all week like nothing ever happened. This is very perplexing to me and I would need some advice for other members. Thanks John L.