[DavGoodlin]

For a similar setup with four VHF channels and broadcast distance less than 100 feet, I use custom cut 1/4 wave antennas on the output of the modulators, located in an attic of my garage, which broadcasts to the house and outbuilding. I picked RF channels that are not active locally. These WILL affect DTV reception and the 65" LCD will scan them all as analog channels. LOL

It sounds like you need an amplifier if you're using more than 50 feet of RG-6 cable, or splitting off to more than 2 sets. Look for Blonder Tongue BIDA-50 or similar amp, that covers up to 500 mhz unless using UHF, then a 750 mhz is better.

The issue with combining analog or digital RF channels is that losses in cable and splitters is different for every channel. Each 2-way splitter drops the signal -3.5 dB. Runs of RG-6 cable typically lose 3.0 dB per 100 feet on VHF High band, RG-11 is about half the RG6 loss and recommended for UHF run over 100 feet

Also important is flatness of response within the 6mhz channel, otherwise sound, video or chroma will be affected. If you can get a spectrum analyzer to look at each channel at each outlet, this is helpful to identify and correct with a gain, "tilt or slope" adjustment that some amplifiers have.