There are splitters, combiners, switches, diplexers, separators, and etc..., each has a purpose, some are combination devices, some are not; but most importantly some should not be used for the wrong purpose.
The DPP44 is a DishPro Plus switch, not a splitter. It is designed to take the signal from upto 4 satellites via DishPro or DishPro Plus LNBF's. These LNBF's uses bandstacking so that each may simultaneous send both polarities of a satellite signal to a switch or receiver at the same time. Then the DPP44 can send the signals of an even transponder and an odd transponder from the same satellite to two different receivers/tuners at the same time. It also has technology to send down a single cable, the same polarity signal from two different satellites at the same time for a dual tuner receiver.
However, this $200 device will not work as a $4 splitter. (Also, it can be a very sensitive device, and any current leaving the TV directly back to the DPP44 could damage it.)
I'm not familiar with the 942, but it sounds like it has a "single agile modulator output" for TV2, where as the 622 has a 'stereo agile modulator output" for TV1 and TV2.
It seems like it would be easy to get coax from the TV2 Output to the other 3 TV's using a 3 way splitter, and without much loss.
There are several ways to accomplish what you want to do, but mainly depending on where your current cable runs are.
If you currently have cables from the other 3 TV to the DPP44 location, you can easily take the TV2 output and send it to a 3-way splitter located near the DPP44 using two methods; (1) run another cable from TV2 output to the 3-way splitter, or (2) more easily would be to buy 2 diplexers ($2 each) and use one of the cables that go from the DPP44 to the 942. The 2 diplexers would combine the 2 signals and then split them when needed.
Looking at your diargram, you desire to take the TV2 output and input it into the DPP44 Satellite Input.
Although this will not work on the DPP44 or the DP34, I believe Sadoun has a generic switch similar to the DP34 that has a Antenna/Cable input built in, which will combine an RF signal with the satellite LNBF signal and send it to the satellite receiver. Then just before the satellite receiver, you use diplexer to separate the signal. However, there may be some drawbacks to using this generic switch, as well as losing the ability to use a single cable for DishPro Plus installations.
Bottom line, I think a $4 3-way splitter is your best bet. And maybe add $4-$5 for a couple of diplexers to avoid another cable run. $10 is better than damaging a $200 DPP44.
EDIT:
Somewhere there are plenty of "distribution diagrams" but I can not find them on the internet right now. I think they are Dish created diagrams. One of several would help, and if I find a link, I'll post it.
Even though I can't use the DPP44 it still sounds like this should be very easy to setup, especially now that I have a more complete diagram to work with!
