That is a viration of what's on my JPG drawing too. However things work differently depending on your rig
Many trailers have the wall-plate with the button and the light, that is the power supply for the pre-amp, if you put a splitter between it and the roof top things do not work.
Usign the diagram in the first PDF, works
Other rigs, such as mine, have a "Flex Vision" type of switch box. this is a advanced switch and in my case it includes several inputs, several outputs, the power supply for the roof, and.... An RF-Modulator for the dvd player (Now that's a box and 3/4)
One of the inputs is "AUX" and is not used at this time
ONe of my converters is going in there... I will put a diplexer (Special splitter which can pass power from the switch box to the roof) in the roof line, the power pass through port to the switch, non-power to the converter, common to antenna. Likely will put my DTV-pal on that one
The insignia will go in the VCR-line The VCR may become a Replay TV though... Replay #2 will go in the bedroom.. it will normally eat off the DTV-Pal
The reason for this has to do with the crappy cable they put in my rig,, UHF does not reach the rear well.
And there are a few other options too, Depending on your existing hardware