I am planning on installing an OTA antenna along with my Dish 622 that I already have. I was going to put the antenna in the attic and hopefully not have to add an additional cable. In the attic I have access to the line going from my 622 to the TV2 so I was hoping I could diplex into that line and split it back out at the 622. I only need to be able to see the antenna with the 622, I don't care to have it shown on TV2. Would it work how I have this drawn up? (blue is my existing setup, red is my proposed addition of the antenna). Is there any other way I could do this without dropping another cable to the 622?