2ndhom......Here is what I did. My DirectTV box came with an HDMI output. If your TV is newer, run an HDMI cable from the DirecTV box to the back of the front TV. The DirecTV box also has RCA (round jacks) on the back for output. Go to Radio Shack, and buy a $20.00 FM Modulator. It allows you to convert the signal from the two RCA jacks on the DirecTV box to coax. Plug the coax cable from the bedroom into the FM modulator coax connection. The modulator needs to be plugged into 110 power.
You'll now how HD TV at the front TV and SD (standard digital) on the rear TV.