Dual output LNBF
I have run into this problem when driving separate receivers. The best thing to do is first of all, install a power inserter (around $40.00) (17H /13V), then a small multiswitch on the output side of the power inserter. Your problems will be solved! I'm not sure why, but some dual output LNBF's get confused when they receive the same voltage on both outputs. By adding the power inserter, this ensures both outputs are running in opposite polarity...