The signal meter on one TV is not necessarily the same as a signal meter on another brand or model. Some meters measure digital error rate, others measure carrier strength and many seem to offer a composite of the two values.
A preamp can only increase the carrier strength. An amplifier has no way to remove on-channel interference which is a dominant cause of digital errors. Because the are many sources of interference, both distant and near, one needs to consider all possible sources of signal impairment when troubleshooting. Amplifiers are not the magic cure for every reception problem.
It sounds as if your signal meter is indicating based on digital error rate. It also sounds as if signal strength is not the reason for signal quality indicating less than 100% error free.
Signal strength is one of many factors that can affect signal quality. But an increase in signal strength does not guaranty an increase signal quality.
If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper.
Last edited by GroundUrMast; 23-Apr-2012 at 7:15 PM.