@GShelton has it right.
I think first you've got some terminology (wording) issues so I will reply with my assumptions of the
correct wording.
First, you have RG6 run through your walls. That *should* be okay.
I've got D* and have it run to 3 different rooms from 1 receiver. (1 composite, 1 component, 2 HDMI) ALL rooms are 'watching' the same channel because primarily it is a 1 person home 8 months of the year.
SOO,
Newer receivers only have HDMI, Component, S-video, and RCA/composite outputs. (Some don't even have all those!) That means running over RG6 is difficult but not imposible. One of my setups runs to an
RF Modulator via composite/RCA and then gets converted to RG6 and finishes the run.
I'm actually in the process of running RG6 to all bedrooms in the home and getting structured media panel with an RF modulator to run out to the rooms via RG6.
That means you may need to stick an RF modulator behind your D* receiver if it doesn't have coax (RG6) out but, that shouldn't be much of an issue, just a minor annoyance.
Also note, if you have HD service, you won't get HD out to that TV and, likely your primary TV will lose its' HD quality because of the conflicting outputs.
I have 26" Full HD monitor that I run to via HDMI and can get D* HD on that if no other TV's are in use but, if the old 26" CRT TV in bedroom 2 is being used (MR. RF Modulator), the receiver yells that it's not an HD connection.
Note on HD:
RG6 can carry 720P HD and up to 1080i (kind-of)
Component can carry 720P and 1080i
HDMI does up to full 1080P