Below is a picture example of what is being talked about.
The basics ... a *diplexer* looks like a splitter .. but in fact it is not ... it is designed to pass satellite frequences and TV-VHF/UHF over the same wire.
when ever you have a "diplexer" installation .. you will have TWO diplexers... One of them will be closer to the Dish Antenna ... the other will be closer to the receiver.
Adding a little confusion ... is that at the receiver (722k) you *will* see a splitter AND a diplexer ... this splitter allows you to have *one* cable come from the satellite dish and feed *both* Satellite IN's on the back.
In the diagram below, you are not looking at the back of a 722k .... but the concept is similar.
the Green Line is would be connected to the "Home Distribution" coax output ... The reason its called home distribution, is because it not only puts out the video for TV2 .... but *also* can put out the video for TV1 The way you see these two different channels, is by turning the TV's channel from say 60 to 62 ... these "broadcast" channels can be changed inside the 722 receiver. (the 722k is "broadcasting" or 'sending out' the signals for the one or two channels that you will see and set-up in menu-6-1-5 which I've documented further below)
As you see in the diagram, the
light blue lines at the receiver.. come from a splitter.. this is the satellite side of the Diplexer ... goes into the red line (the main cable from the dish antenna) and then somewhere else on that line, is where the second diplexer is ... from the TV side of the second Diplexer ... you have a branch that currently feeds your second TV .. its *that* line (represented by the dark blue lines) that you want to add a splitter to, to allow you to get the 3rd TV up and running.
Menuing commands...
From TV 1 ....
Menu - 6 - 1 - 5
(Menu - 6 "System Setup" - 1 "Installation" - 5 "Modulator Setup")
- First.. set the *MODE* for both TV1 and TV2 out to be the same.
If TV2 is already set for Cable, set TV1 for "Cable".
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- Make note of the channels. This is where you set which channel is being "broadcast" on the Coax cable that you will split to your 2nd & 3rd TV's tuners.
example: If TV1 out is on 60, and TV2 out is 62 ... then at your 2nd TV, after hitting "done" and before changing any cable connections.. you should be able to scan for channels.. and should be able to get both 60 and 62 (again what ever your screen says in this menu, are the channels you will be using at TV2 and later at TV3 when hooked up, and this may be different on *your* 722k, but I'm referencing 60/62 here) ... going to TV2 and tuning to the channel numbers you saw/set in Menu-6-1-5, you will find that "60" is the same as TV1/Tuner1 ... "62" would be TV2/Tuner2.
Note when coming out of this menu you will be asked if you are connecting directly to the TV ... you want to be in distribution mode ... this sends a little more power onto the line because each time you split it, it will drop the amount of power each split leg receives. (new splitters usually show this as -3.5 at each of the "out" ports on a splitter).
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- Once you have both TV1 and TV2 appearing on your 2nd TV, by changing the 2nd TV's tuner/station ... *then* insert your splitter in TV2's cable line .. but *before* the line reaches back to the diplexer
Again, this is the *dark blue* lines you see from the TV's in the diagram, going to the "Coax Splitter".. the "input" of the splitter is what goes to the Diplexer
I hope that diagram clears up what you *logically* should have.
I say "logically" because as you admitted .. you had techs there..and it took them 2 days of fumbling with reusing the inhouse cable to make the connections work...
the only difference in that diagram ... is that what you want to do is shown with the Dark Blue lines.. a splitter connected to the TV LEG of the Diplexer, so you can put two TV's out.