Diplexers

If you're reading this hopefully you know more about this device than me.

I ordered directtv and already have roadrunner.

Well directtv showed up today and said my new place was only wired for cable or something.

I had no clue this would be a problem

So I can not run directtv and roadrunner through the same coaxial jack downstairs and I only have one coaxial jack down stairs.

And my stuff downstairs isn't wireless and I don't feel like running 25 ft cat5 cords from upstairs to downstairs

I finally said screw it directtv, you are to much of a hassle. And told the install guy to just stop and i'm not interested

The tech finally said he had these diplexers that he can try and he explained what they do so I said give it a try, i'm at work so i'm doing everything over the phone with him as my wife has no clue what hes doing either.

Now I did some reading.. are the directtv techs not supposed to do this?

Will I take a massive quality hit??

I don't think a DirecTV tech is going to help you with a cable modem connection -- most are local independent contractors who barely know how to hook up DTV, let alone a cable modem.

Diplexers are used to combine digital satellite signals with analog TV signals on the same cable. One diplexer combines them at the source end, and another separates them again at the destination satellite tuner/TV. Digital satellite signals run at a much higher frequency than analog cable signals, and because the frequencies are so distinct, it's easy to electrically combine/separate them. AFAIK this frequency modulation/demodulation only works with analog cable/antenna signals -- I seriously doubt a digital cable modem signal can be reliably modulated on a satellite signal because I would guess they are of similar frequencies. You can try it, but I'd be surprised if it worked very well, especially with off-the-shelf ordinary diplexers, which are designed for digital+analog, not digital+digital.

Well the guys finished up and I'm told everything works and looks great so far, i'll see for myself when I get home