I have some in-house TV channels I distribute throughout the house on coax that "piggy-backs" my current satellite signals then get diplexed out at each wall jack. I'm getting ready to switch over to U-Verse and wondering if I can retain my in-house channels on the same coax the RG will be distributing on the existing coax. Is that possible? Thanks.
If you have a use for the existing cabling in your home, then the installer should run new lines from the RG to that room. Coupling any transmissions over U-verse used lines are not a good idea, and most likely will impare service. Unless you have an impossible cable run to that room, your installer should not need to use that line.
I suggest using the telephone wiring instead. I have cable provided by my Home Owners Association and have retained the cable on my coax. The UVerse is provisioned through the telephone wiring and is connected to my Video 1 input on my TV. If you do not have more than 1 input, on your TV, I suggest an a/b switch.
I honestly don't see the harm in it as long as you keep the RF signals on the HPNA/RF side of the diplexer if they bring VDSL in on coax (if they bring VDSL in on TP, you should still be fine). The HPNA over coax spec was deliberately designed out of range of TV signals so that modulated RF and other forms of TV can co-exist with the HPNA signal, just like HPNA was originally designed out of the range that phones use so that you can use the phone wiring for HPNA while still being able to use your phone on the same pair.