Don't be a penny pincher, trying to do it on the cheap.
Buy a distribution amplifier like this.
https://www.amazon.com/Channel-Maste.../dp/B001PI09SE
Connect the input of the distribution amp to the output jack on your antenna power supply. Then powers all your sets from the output of the distibution amp.
With a distribution amplifier, you will not have any signal loss. If a 3DB signal goes in, you will get a 3db signal on every output jack of the amp.
I use several of these in my system. I tried using standard splitters like you have first, and had huge signal loss causing pixelation. Then I started using these distribution amps and I get excellent signal strength to all 15 sets that I currently have wired in my display room. I use a powered UHF rotor antenna like you are probably using too.
Also see this page on my web site
http://antiquetvguy.com/WebPages/FAQ...%20Signal.html