I had the antenna sitting on a dense foam "bridge" that was wedged between the back of the DLP and the wall. The antenna was pretty much level with the top of the TV. I used the same exact set up with the flat panel and signal reduction was immediate.
The old set up limits the vertical adjustment of the
Jensen's rabbit ears, but signals were fine. I now have the antenna behind the panel sitting atop a 20" block, which allows vertical freedom. Signals are a little better on the block instead of on the "bridge". None the less, I can't do anything to get strength back to what it was with the DLP.
I am looking into getting a new indoor antenna. Either the Winegard SS 3000 or the Terk imitation (HDTVLP) of the Winegard, or a Terk TV5. An outdoor antenna is out of the question. Having the dish on top of our apartment on a sled is really pushing things. So, an indoor antenna is a must.