I have been using one of these for about 3 years. The first year and a half it worked fine. I was modulating A on Channel 80, and B on Channel 82. Suddenly 82 became unwatchable. I assumed this was due to a change in my cable stream. I wound up buying another unit only to experience the exact same results. I returned it, and started modulating on only channel 80 and adding a multi switch into the equation, which allowed me to switch between multiple sources.
Yesterday I started playing around again. It seemed that I could modulate the B modulator to 80, but the A, no matter where I set it, would show up in the channel lineup around 69. I finally found that putting it at 100 worked ok. I suppose this is a solution to my problem, and everything is ok for now. But I'm curious as to what caused this. Any ideas? Maybe a Channel Plus guru can shed some light.