There was a thread on pixelation a little while ago. I discovered that there were 2 megawatt chans on the same tower transmitting on adjacent frequencies. The second case involved transmitters on different towers about a mile apart. The FCC really screwed up by allowing transmitters on adjacent frequencies so close together.
The last thing I did that helped some but didn’t cure the problem was point my antenna 30 degrees off axis. That reduced the strength of all chans and dropped strength of the channel adjacent to the one that I am tuned to below the point where it doesn’t drive thru the intermediate frequency amplifier as much and might not be detected.
Take a look at the thread.