@agthad--
Know that not all antennas are create equal (some work better for some scenarios, others better for others), though I think they all work equally well when given relatively decent signal strengths. There are TONS of antenna discussions here on AVS as well. I got sucked into the DIY approach because I wanted to pick up a specialty station far away.
Also, the digital audio signal is embedded within the ATSC channel encoding, so the TV's digital output "signal level" has nothing to do with the antenna strength, except that if the antenna strength is "marginal" the tuner/decoder may have too low a SNR (signal-to-noise ratio), that is.. too much noise, to properly decode the audio signal. That wouldn't cause a lower output signal, just a choppy one. The TV's internal electronics however may provide a low output signal (regardless of OTA signal strength). Which is why you'll also need to look up threads about your particular TV. For instance, some TV's are known to not interoperate well with Onkyo receivers... yours might also have some known "features."

And yes, RG6QS works better than RG59. Some amplifiers will amplify the noise just as much as the signal. It's not the "power" that matters, it's the signal to noise ratio. A good LNA (low noise amplifier) will cost more than a standard "so-so" amplifier. But, something is better than nothing, so give it a shot and let us know.
good luck, keep us posted,
..dane