I run hd cctv to all the TV's in the house, and although I do use a matrix for other things its actually quite straightforward without.
TV areal comes into the house and into the loft where it enters a signal booster and is distributed by coax to all of the rooms with a TV point - standard distribution setup.
So I added one of these TV modulators and distribute cctv around the house.....https://www.amazon.co.uk/Edision-HDMI-M ... +modulator
The setup now is ....
TV areal comes into the house and into the modulator in. The CCTV DVR out (HDMI) also goes into the modulator. The out from the modulator goes into the signal booster and is distributed via coax. Result CCTV on every TV for when the door bell rings, or if needed at any time. My modulator is set to 'broadcast' on channel 999 (emergency services number in the UK). Just switch TV to channel 999 and you have the CCTV.
I have actually added a second modulator with an ATV and whilst not 4k, works perfectly controlled via the iphone app. Pause and resume in another room etc etc. if you added a matrix prior to the modulator input, you could have multiple inputs....selected by a little Indigo automagic.
Not sure why it would interfere with MOCA, as its only injecting another digital TV channel into what the areal is receiving, although not specifically looked into that. I would guess the modulator may need to be inserted before any MoCA kit.
EDIT Note that the Tv's need to be able to decode DVB-T2 which is the standard broadcast signal in the UK . There may be other similar units for other HD decoders in other parts of the world.
EDIT 2: Heres a similar modulator for the US, but not tried this (obviously) https://www.amazon.com/MINIMOD-2-MODULA ... +Modulator