"If it's a amplified antenna then there is a separate power supply in the rig that supplies 12V to the antenna and TV signal to the receiver."
My post was in response to the OTA coax input on the back of the DTV receiver and back in the day on VHS recorders. No 12 volts.
AFTER I posted, a post was made describing an OTA Coax input on the DTV Antenna. I made no representation about that connection and candidly have no idea if an RV would have such a setup.
In the interest of my learning, if not hijacking this thread, I do not see why 12 volts would have anything to do with the OTA signal. The OTA Coax input at the Dish antenna is simply Diplexed with the Sat Signal and thus uses the single Coax from the Antenna to the receiver. No external voltage is required to diplex these two signals. On the back of the receiver is a second (unpowered) Diplexer that separates the Sat and OTA signals into two coax inputs to the back of the receiver.
The 12 volts is power for the LNB(s) and has nothing to do with Diplexing. Yes?