Hi guys!
Yeah - I've talked about the transmitting of TV2 out the UHF remote antenna before.
Since then, I've done some testing, and while it might not be legal, I agree it's NOT going to be a problem.
Now, the combining/diplexing concept. It's easy if you understand the CONCEPT.
Splitters/Combiners work in one frequency band (for our purposes VHF/UHF - 50-850MHz). You can use them as much as desired with two considerations. First, no same channel from more than one source. Second, a splitter introduces signal loss, so every one shortens your maximum working distances.
Our diplexers have band-pass filters. One port is for low-band, the other for high-band (900-2150+ MHz). Knowing that, plug satellite stuff into satellite stuff, and VHF/UHF into VHF/UHF. The combined ports ALWAYS face each other on the cable. Done deal.
Last consideration with all these boxes is if a power inserter (DPP44, SW64, OTA antenna or rotor) is involved. Rule of thumb is to NOT box any of these boxes between a power inserter can and the device being powered. Exception is if you KNOW the box is rated to carry high current.