Ok, I've got a messed up setup here from what I can tell, I left it to a professional to install while the house was being renovated and didn't have a chance to question any of it at the time. Here's the setup: - TV aerial goes to Antiference MHK4LTE 4-channel Masthead Amplifier in the loft. It doesn't seem to have any power supply, even though it seems it's supposed to. - From that only one of the outputs is used, which goes down 2 floors to my media cupboard and plugs into a Triax SCS-4 4-way splitter. - The outputs from this go to the 4 coax points at various points in the house (1 on ground floor, 2 on first floor and 1 on top floor) If I plug the aerial directly into a TV using an F-type to Coax connector I get a perfect signal, with 175+ channels (TV & radio I guess) found. If I plug the TV into one of the wall sockets fed by the splitter in the cupboard, I get around 50 channels but they mostly break up. Not knowing anything about this it seems as if the Masthead Amplifier should be powered by a 12v PSU that takes the aerial feed and outputs the TV feed to the amplifier box. I can't find this PSU anywhere in the loft, and I can confirm that the aerial was directly connected to the input on the amplifier (this seems to be where the output from the PSU should go) I don't really know why I need a 4 channel amplifier at all when all the wall plates are wired to the splitter downstairs? Wouldn't I just need a 1 channel amplifier in the loft? Also - do I need a "set back" amplifier in place of the Triax SCS-4 passive splitter downstairs? Would amplifying the signal twice cause problems? (Don't ask why the 4 outputs on the Masthead Amplifier aren't the ones going to the wall plates around the house - I don't know why it was done this way, and I have to deal with it now) Thanks in advance!