Hi BigJ sorry for not replying sooner. Merry x-mas.
You could always try a
Diplexer
That should end your Signal Woes.
Your model has 2 ports. One SD the other HD.
When you attach your TV to it. You go through the HD.
When you record through the Air HD. Your DVR will limit you to SD.
But only on pre-selected channels. Chosen by the the RIAA.
Blame the RIAA on that one.
As you can see no matter how many times you try. Your never are going to be able to record in HD.
Since your DVR is included in with your SAT. The DVR must feed off from the SAT. And dishnetwork put restrictions on any outside HD. Meaning over the Air channels. There is the use of
SlingBox though.
But with the use of the Diplexer that will keep you from switching back and forth in turn. You should receive those missing channels.
You can get a Diplexer
Here.