After some more thought. You are going to have a problem with combining after the modulator. Injecting the whole Comcast line-up is going to interfere with your modulator outputs at 92 and 102. If you have the option of moving your outputs up to 117 and higher to get above 750MHz. This will work until Comcast upgrades their headends to 1gig. Or you will need to filter out channel 100 and up. This will be tricky because you don’t know exactly where the local HD channels are located in the line-up.
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