Can TV Tuner card signals be mixed to receive from both ATSC and QAM signals simultaneously?

yes

that actual relies upon. you're able to desire to evaluate the alerts accessible to you. The sat field takes RF from the satellite tv for pc LNBs and demodulates it to video and audio or remodulates video and audio to RF as NTSC analog channels 3 or 4. in case your workstation tuner additionally has a video and audio enter of a few style, you should use a video and audio output from the sat field. in case your workstation tuner additionally gets NTSC, you should use the analog channel 3 or 4 RF output of the sat field. The sat field RF output does not output ATSC digital. in case your workstation tuner has neither an NTSC analog tuner nor a video and audio enter, you won't be in a position to apply it to bypass RF or video and audio out of your sat field on your workstation, you're able to desire to get another form of gadget to attach on your workstation, ideally something which will seize video and audio extremely than purely an RF tuner with ATSC/QAM decoder.

Not really. ATSC and QAM have different channel allocations, so the tuner needs to scan every time you switch so that it can create its channel table.

You need two cards to do what you want to do.