Installed hr34 and hr23, swm8 and am21 atsc off air tuner on the hr34. Off air showing on hr34 fine but absent on hr23. In hr23 setup, no ant. Sub menu found either. I assume Atsc signal is not being passed from hr34 to hr23.
1. Did I not set up something properly or is that the system limitations, not passing off air channels to hr23 normal? Dtv tech is clueless.

2. Can I send output of am21 to ant. Input on swm8 and distribute it that way?

I see that one way is to input ota antenna directly into ant. Input on swm8 then split it out before hr34 and hr23 input but there is only 1 coax input on receivers so do I then need two am21's, one for each reciever? Or is there a simpler option? The ota signal from at21 to hr34 is via USB so if I send it to the swm8 I will need to convert the USB to coax, is that possible in this case?